Information signal processing device, information signal processing method, image signal processing device, image display comprising the same, coefficient type data creating device and method used for the same, and information providing medium

ABSTRACT

The present invention relates to an information signal processor and the like preferable for use in the case of converting a format of an image signal or converting an image size. An input image signal Vin ( 525   i  signal) is converted into an output image signal Vout (such as  1080   i  signal, XGA signal, or  525   i  signal for obtaining an image to be displayed in a different magnification). A class code CL is obtained from tap data selectively extracted from the Vin and corresponding to each pixel (pixel at a target position) within a unit pixel block, which constitutes Vout. A coefficient production circuit 136 produces coefficient data for each class, which is used at the time of calculating the pixel data at the target position, based on the coefficient seed data for each class and phase information h, v about the target position generated in a phase information generation circuit  139.  A calculation circuit  127  provides pixel data y 1  to yp of the target position according to the estimated equation using the tap data xi corresponding to the target position and the coefficient data Wi corresponding to the class code CL.

TECHNICAL FIELD

[0001] The present invention relates to an information signal processor,a method for processing an information signal, an image signal processorand an image display apparatus using the same, a device and a method forproducing coefficient seed data used in the same, and aninformation-providing medium, which are preferable for use in the caseof, for example, converting a format of an image signal or converting asize of an image.

[0002] More specifically, the present invention relates to aninformation signal processor and the like whereby, when converting afirst information signal into a second information signal, phaseinformation about a target position in the second information signal isobtained from the information about format or size conversion, and basedon the resultant phase information, coefficient data of an estimatedequation is produced from coefficient seed data, and information data ofthe target position in the second information signal is obtained usingthus-produced coefficient data, thereby allowing a memory for storing alarge amount of coefficient data at the time of making conversions intovarious formats and sizes to be eliminated.

BACKGROUND ART

[0003] In order to convert formats or image sizes, it is required toacquire pixel data having a phase different from a phase of pixel dataof an input image signal so as to obtain an output image signal. In thiscase, the format or the image size thus converted makes a phaserelationship of the pixel of the output image signal to the pixel of theinput image signal univocally determined.

[0004] As an example of a format conversion, description will be made asto a case where an input image signal is a 525 i signal and an outputimage signal is a 1080 i signal. The 525 i signal means an image signalin an interlace system consisting of 525 lines. The 1080 i signal meansan image signal in an interlace system consisting of 1080 lines. FIG. 14shows a positional relationship between the pixels of the 525 i signaland the pixels of the 1080 i signal. Herein, large dots are pixels ofthe 525 i signal, and small dots are pixels of the 1080 i signal. Solidlines express the positions of pixels in odd fields and broken linesexpress the positions of pixels in even fields.

[0005] When converting the 525 i signal into the 1080 i signal, it isrequired to obtain a pixel block in the unit of 9×9 of the 1080 i signalin correspondence with each pixel block in the unit of 4×4 of the 525 isignal in the respective odd and even fields.

[0006]FIG. 15 shows a phase relationship in a vertical direction betweenthe pixels of the 525 i signal and the pixels of the 1080 i signal. InFIG. 15, the numerical value assigned to each pixel of the 1080 i signalmeans a shortest distance from the pixel of the 525 i signal in avertical direction. In this case, the interval between the pixels of the525 i signal in a vertical direction is set to 16. In this manner, eachof the numerical values assigned to each pixel of the 1080I signal showsphase information of this pixel in a vertical direction with respect tothe pixel of the 525 i signal.

[0007] The phase information is set to a negative value when the pixelof the 1080 i signal is located at a position upper than the pixel ofthe 525 i signal (i.e. a pixel located at the shortest distance fromthis pixel of the 1080 i signal), while it is set to a positive valuewhen the pixel of the 1080 i signal is located at a position lower thanthe pixel of the 525 i signal. The same thing is applied to the drawingshowing a phase relationship in a vertical direction between an extendedgraphics array (XGA) signal, which will be described later, and the 525i signal.

[0008]FIG. 16 shows a phase relationship in a horizontal directionbetween the pixels of the 525 i signal and the pixels of the 1080 isignal. In FIG. 16, the numerical value assigned to each pixel of the1080 i signal means a shortest distance from the pixel of the 525 isignal in a horizontal direction. In this case, the interval between thepixels of the 525 i signal in a horizontal direction is set to 8. Inthis manner, each of the numerical values assigned to the pixel of the1080 i signal shows phase information of this pixel in a horizontaldirection with respect to the pixel of the 525 i signal.

[0009] The phase information is set to a negative value when the pixelof the 1080 i signal is located at a position more left to the pixel ofthe 525 i signal (i.e. a pixel located at the shortest distance fromthis pixel of the 1080 i signal) while it is set to a positive valuewhen the pixel of the 1080 i signal is at a position more right to thepixel of the 525 i signal. The same thing is applied to the drawingshowing a phase relationship in a horizontal direction between the XGAsignal, which will be described later, and the 525 i signal.

[0010] Next, as an example of a format conversion, description will bemade as to a case where an input image signal is a 525 i signal and anoutput image signal is an XGA signal. The XGA signal is an image signalin a progressive system (i.e. non-interlace system) available at adisplay with a resolution of 1024×768 dots. FIG. 17 shows a positionalrelationship between the pixels of the 525 i signal and the pixels ofthe XGA signal. Herein, large dots are pixels of the 525 i signal, andsmall dots are pixels of the XGA signal. In addition, as to the 525 isignal, solid lines express the positions of pixels in odd fields andbroken lines express the positions of pixels in even fields.

[0011] When converting the 525 i signal into the XGA signal, it isrequired to obtain a 8×16 pixel block of the 1080 i signal incorrespondence with each 5×5 pixel block of the 525 i signal in therespective odd and even fields.

[0012]FIG. 18 shows a phase relationship in a vertical direction betweenthe pixels of the 525 i signal and the pixels of the XGA signal. In FIG.18, each of the numerical values assigned to the pixels of the XGAsignal means a shortest distance from the pixel of the 525 i signal in avertical direction. In this case, the interval between the pixels of the525 i signal in a vertical direction is set to 16. In this manner, eachof the numerical values assigned to the pixels of the XGA signal showsphase information of this pixel in a vertical direction with respect tothe pixel of the 525 i signal.

[0013]FIG. 19 shows a phase relationship in a horizontal directionbetween the pixels of the 525 i signal and the pixels of the XGA signal.In FIG. 19, each of the numerical values assigned to the pixels of theXGA signal means a shortest distance from the pixel of the 525 i signalin a horizontal direction. In this case, the interval between the pixelsof the 525 i signal in a horizontal direction is set to 8. In thismanner, each of the numerical values assigned to the pixels of the XGAsignal shows phase information of this pixel in a horizontal directionwith respect to the pixel of the 525 i signal.

[0014] Although an example of image size conversion is not specificallyshown, the phase relationship of the pixels of the output image signalto the pixels of the input image signal is uniquely determined, as isthe case of the format conversion described above. For example, in thecase where the size of an image (magnification of a displayed image) ismagnified by {fraction (9/4)} times in both vertical and horizontaldirections, the same phase relationship is obtained as the phaserelationship between the 525 i signal and the 1080 i signal describedabove.

[0015] Conventionally, it has been suggested to employ the followingmethod at the time when pixel data of an output image signal is to beobtained from pixel data of an input image signal in order to convertformats or image sizes. That is, coefficient data of an estimatedequation corresponding to each phase of the pixel of the output imagesignal with respect to the pixel of the input image signal is stored ina memory. Then, by use of thus-obtained coefficient data, pixel data ofthe output image signal is obtained by the estimated equation.

[0016] As described above, if the format or the image size is differentbetween before and after the conversion, then the phase relationship ofthe pixels of the output image signal to the pixels of the input imagesignal becomes different between before and after conversionaccordingly. For this reason, in an apparatus in which a memory storescoefficient data of an estimated equation, when conversions into variousformats or sizes are performed, it is required to store coefficient datainto the memory in correspondence with each format or size. In such acase, it is required to install a memory capable of storing a largeamount of coefficient data. This causes inconvenience that theconversion apparatus becomes expensive, and the like.

DISCLOSURE OF INVENTION

[0017] An objective of the present invention is to provide aninformation signal processor and the like which allows a memory forstoring a large amount of coefficient data in order to make conversionsinto various formats or sizes to be eliminated.

[0018] An information signal processor in accordance with the presentinvention for converting a first information signal including aplurality of information data into a second information signal includinga plurality of information data, comprises conversion information inputmeans for inputting conversion information about a format or sizeconversion, information conversion means for converting the conversioninformation input by the conversion information input means into phaseinformation about a target position in the second information signal,first memory means for storing coefficient seed data, the coefficientseed data being coefficient data in production equation for producingcoefficient data to be used in an estimated equation and said productionequation using the phase information as a parameter, coefficient datageneration means for generating the coefficient data to be used in theestimated equation corresponding to the phase information about thetarget position, the coefficient data in the estimated equation beingproduced according to the production equation using the coefficient seeddata stored in the first memory means and the phase information aboutthe target position obtained as a result of conversion in theinformation conversion means, first data selection means for selecting aplurality of first information data located in periphery of the targetposition in the second information signal, based on the firstinformation signal, and calculation means for calculating and obtaininginformation data of the target position based on the estimated equationusing the coefficient data generated in the coefficient data generationmeans and the plurality of first information data selected in the firstdata selection means.

[0019] Further, a method for processing an information signal inaccordance with the present invention for converting a first informationsignal including a plurality of information data into a secondinformation signal including a plurality of information data comprises afirst step of inputting conversion information about a format or sizeconversion, a second step of converting the conversion information inputin the first step into phase information about a target position in thesecond image signal, a third step of generating coefficient data to beused in estimated equation corresponding to the phase information aboutthe target position obtained as a result of the conversion in the secondstep according to production equation for producing coefficient data tobe used in the estimated equation using coefficient seed data and thephase information about the target position, the production equationusing the phase information as a parameter, and the coefficient seeddata being coefficient data in the production equation, a fourth step ofselecting a plurality of first information data located in periphery ofthe target position in the second information signal based on the firstinformation signal, and a fifth step of calculating and obtaininginformation data of the target position based on the estimated equationusing the coefficient data generated in the third step and the pluralityof first information data selected in the fourth step.

[0020] Further, an information-providing medium in accordance with thepresent invention provides a computer program for executing each step inthe method for processing the information signal described above.

[0021] Further, an image signal processor in accordance with the presentinvention for converting a first image signal including a plurality ofpixel data into a second image signal including a plurality of pixeldata, comprises conversion information input means for inputtingconversion information about a format or size conversion, informationconversion means for converting the conversion information input by theconversion information input means into phase information about a targetposition in the second image signal, memory means for storingcoefficient seed data, the coefficient seed data being coefficient datain production equation for producing coefficient data to be used inestimated equation, the production equation using the phase informationas a parameter, coefficient data generation means for generating thecoefficient data to be used in the estimated equation corresponding tothe phase information about the target position, the coefficient data inthe estimated equation being produced according to the productionequation using the coefficient seed data stored in the memory means andthe phase information about the target position obtained as a result ofconversion in the information conversion means, data selection means forselecting a plurality of pixel data located in periphery of the targetposition in the second image signal, based on the first image signal,and calculation means for calculating and obtaining pixel data of thetarget position based on the estimated equation using the coefficientdata generated in the coefficient data generation means and theplurality of pixel data selected in the data selection means.

[0022] Further, an image display apparatus according to the presentinvention comprises image signal input means for inputting a first imagesignal including a plurality of pixel data, image signal processingmeans for converting the first image signal input from the image signalinput means into a second image signal including a plurality of pixeldata and for outputting the resultant second image signal, image displaymeans for displaying an image produced by the second image signalreceived from the image signal processing means onto an image displayelement, and conversion information input means for inputting conversioninformation corresponding to a format or a size of the image displayedon the image display element. The image signal processing means includesinformation conversion means for converting the conversion informationinput by the conversion information input means into phase informationabout a target position in the second image signal, first memory meansfor storing coefficient seed data, the coefficient seed data beingcoefficient data in production equation for producing coefficient datato be used in estimated equation, and the production equation using thephase information as a parameter, coefficient data generation means forgenerating coefficient data to be used in the estimated equationcorresponding to the phase information about the target position, thecoefficient data in the estimated equation being produced according tothe production equation using the coefficient seed data stored in thefirst memory means and the phase information about the target positionobtained as a result of conversion in the information conversion means,first data selection means for selecting a plurality of first pixel datalocated in periphery of the target position in the second image signal,based on the first image signal, and calculation means for calculatingand obtaining pixel data of the target position based on the estimatedequation using the coefficient data generated in the coefficient datageneration means and the plurality of first pixel data selected in thefirst data selection means.

[0023] According to the present invention, the conversion informationabout the format or size conversion is input and this conversioninformation is converted into the phase information about the targetposition in the second information signal. Herein, the informationsignal is a signal such as an image signal and a sound signal. When theinformation signal is the image signal, the format or the image sizeafter the conversion makes the phase relationship of the pixels of theoutput image signal to the pixels of the input image signal uniquelydetermined. In addition, the plurality of first information data locatedin periphery of the target position in the second information signal isselected according to the first information signal.

[0024] Then, the information data of the target position is obtainedcorresponding to the phase information about the target position in thesecond information signal. Specifically, the memory means stores thecoefficient seed data, which is coefficient data in the productionequation for producing the coefficient data to be used in the estimatedequation. By use of this coefficient seed data and the phase informationabout the target position in the second information signal, coefficientdata in the estimated equation corresponding to the phase informationabout this target position is generated. Then, by use of thus-generatedcoefficient data and the plurality of the first information data,information data of the target position is produced based on theestimated equation.

[0025] According to the invention described above, when the firstinformation signal is to be converted into the second informationsignal, the phase information about the target position in the secondinformation signal is obtained from the conversion information about theformat or size conversion, the coefficient data in the estimatedequation is produced from the coefficient seed data based onthus-obtained phase information, and the information data of the targetposition in the second information signal is obtained using thecoefficient data. Therefore, the memory stores no coefficient datacorresponding to various formats and sizes so that there is no need of amemory for storing a large amount of coefficient data on the conversionsinto various formats or sizes are performed.

[0026] When a sum of the coefficient data of the estimated equationproduced using the coefficient seed data is obtained and then theinformation data of the target position produced using the estimatedequation as described above is normalized with it being divided by thesum, it becomes possible to remove the fluctuations in the levels fromthe information data of the target position caused by a rounding errorwhich occurs at the time when the coefficient data of the estimatedequation is obtained by the production equation using the coefficientseed data.

[0027] Further, a coefficient seed data production device in accordancewith the present invention for producing coefficient seed data, thecoefficient seed data being coefficient data in a production equationfor producing coefficient data to be used in estimated equation employedwhen converting a first information signal including a plurality ofinformation data into a second information signal including a pluralityof information data, the production equation using phase information asa parameter, comprises signal processing means for performing athinning-out processing on a teacher signal to obtain a student signal,phase shift means for shifting a phase of the student signal with aphase of information data position of the teacher signal being graduallychanged with respect to the information data position of the studentsignal, first data selection means for selecting a plurality of firstinformation data located in periphery of a target position in theteacher signal, based on the student signal having a phase shifted bythe phase shift means, normal equation production means for producing anormal equation for obtaining the coefficient seed data using theplurality of the first information data selected by the first dataselection means and the information data at the target position in theteacher signal, and coefficient seed data calculation means for solvingthe normal equation to obtain the coefficient seed data.

[0028] Further, a method for producing coefficient seed data inaccordance with the present invention for producing coefficient seeddata used for producing coefficient data to be used in an estimatedequation employed when converting a first information signal including aplurality of information data into a second information signal includinga plurality of information data, the coefficient seed data beingcoefficient data in a production equation using phase information as aparameter, comprises a first step of performing a thinning-outprocessing on a teacher signal to obtain a student signal, a second stepof shifting a phase of the student signal with the phase of informationdata position of the teacher signal being gradually changed with respectto the information data position of the student signal, a third step ofselecting a plurality of information data located in periphery of atarget position in the teacher signal, based on the student signalhaving a phase shifted in the second step, a fourth step of producing anormal equation for obtaining the coefficient seed data using theplurality of the information data selected in the third step and theinformation data at the target position in the teacher signal, and afifth step of solving the normal equation produced in the fourth step toobtain the coefficient seed data.

[0029] Further, an information-providing medium in accordance with thepresent invention provides a computer program for executing each step inthe method for producing the coefficient seed data described above.

[0030] According to the present invention, the thinning-out processingis performed on the teacher signal to obtain the student signal. Whenthe 1050 i signal is illustratively used as the teacher signal, thethinning-out processing is performed .on the 1050 i signal to obtain 525i signal as the student signal. Then, the phase of the student signal isshifted with a phase of the information data position of the teachersignal being gradually changes with respect to the information dataposition of the student signal.

[0031] A plurality of information data located in periphery of thetarget position in the teacher signal is selected on the basis of thephase-shifted student signal. Then, by use of thus-selected plurality ofinformation data and the information data of the target position in theteacher signal, a normal equation for obtaining the coefficient seeddata is produced. This equation is then solved to obtain the coefficientseed data.

[0032] Herein, the coefficient seed data is coefficient data in theproduction equation for producing coefficient data to be used in theestimated equation employed when converting the first information signalinto the second information signal, the production equation using thephase information as a parameter. Using this coefficient seed dataallows the coefficient data corresponding to arbitrary phase informationto be obtained according to the production equation. As a result ofthis, when converting the format or the size, the coefficient data ofthe estimated equation is produced from the coefficient seed data on thebasis of the phase information about the target position in the secondinformation signal so that it can obtain the information data of thetarget position using thus-produced coefficient data.

[0033] Further, a coefficient seed data production device in accordancewith the present invention for producing coefficient seed data, thecoefficient seed data being-coefficient data in production equation forproducing coefficient data to be used in estimated equation employedwhen converting a first information signal including a plurality ofinformation data into a second information signal including a pluralityof information data, and the production equation using phase informationas a parameter, comprises signal processing means for performing athinning-out processing on a teacher signal to obtain a student signal,phase shift means for shifting a phase of the student signal with aphase of information data position of the teacher signal being graduallychanged with respect to the information data position of the studentsignal, first data selection means for selecting a plurality of firstinformation data located in periphery of a target position in theteacher signal, based on the student signal having a phase shifted bythe phase shift means, first normal equation production means forproducing a first normal equation for obtaining the coefficient data ofthe estimated equation per phase shift value of the student signal usingthe plurality of the first information data selected in the first dataselection means and the information data at the target position in theteacher signal, coefficient data calculation means for solving the firstnormal equation to obtain the coefficient data of the estimated equationper the phase shift value, second normal equation production means forproducing a second normal equation for obtaining the coefficient seeddata using the coefficient data per the phase shift value obtained inthe coefficient data calculation means, and coefficient seed datacalculation means for solving the second normal equation to obtain thecoefficient seed data.

[0034] Further, a method for producing coefficient seed data inaccordance with the present invention for producing coefficient seeddata, the coefficient seed data being coefficient data in productionequation for producing coefficient data to be used in estimated equationemployed when converting a first information signal including aplurality of information data into a second information signal includinga plurality of information data, and the production equation using thephase information as a parameter, comprises a first step of performing athinning-out processing on a teacher signal to obtain a student signal,a second step of shifting a phase of the student signal with a phase ofinformation data position of the teacher signal being gradually changedwith respect to the information data position of the student signal, athird step of selecting a plurality of information data located inperiphery of a target position in the teacher signal, based on thestudent signal having a phase shifted in the second step, a fourth stepof producing a first normal equation for obtaining the coefficient dataof the estimated equation per phase shift value of the student signalusing the plurality of the information data selected in the third stepand the information data at the target position in the teacher signal, afifth step of solving the first normal equation produced in the fourthstep to obtain the coefficient data of the estimated equation per thephase shift value, a sixth step of producing a second normal equationfor obtaining the coefficient seed data using the coefficient data perthe phase shift value obtained in the fifth step, and a seventh step ofsolving the second normal equation produced in the sixth step to obtainthe coefficient seed data.

[0035] Further, an information-providing medium in accordance with thepresent invention provides a computer program for executing each step inthe method for producing the coefficient seed data described above.

[0036] According to the present invention, the thinning-out processingis performed on the teacher signal to obtain the student signal. Whenthe 1050 i signal is illustratively used as the teacher signal, thethinning-out processing is performed on the 1050 i signal to obtain 525i signal as the student signal. Then, the phase of the student signal isshifted with the phase of the information data position of the teachersignal being gradually changes with respect to the information dataposition of the student signal.

[0037] A plurality of information data located in periphery of thetarget position in the teacher signal is selected on the basis of thephase-shifted student signal. Then, by use of thus-selected plurality ofinformation data and the information data of the target position in theteacher signal, a first normal equation for obtaining the coefficientdata of the estimated equation is produced at every phase shift value ofthe student signal. This equation is then solved to obtain coefficientdata of the estimated equation at every phase shift value.

[0038] Further, by use of the coefficient data at every phase shiftvalue, a second normal equation for obtaining coefficient seed data isproduced. This equation is then solved so as to obtain coefficient seeddata.

[0039] Herein, the coefficient seed data is coefficient data in theproduction equation for producing the coefficient data to be used in theestimated equation employed when converting the first information signalinto the second information signal, the production equation using thephase information as parameter. Using this coefficient seed data allowsthe coefficient data corresponding to arbitrary phase information to beobtained according to the production equation. As a result of this, atthe time of the format or size conversion, the coefficient data of theestimated equation is produced according to the coefficient seed databased on the phase information about the target position in the secondinformation signal. Then, by use of thus-produced coefficient data, itbecomes possible to obtain the information data of the target position.

BRIEF DESCRIPTION OF THE DRAWINGS

[0040]FIG. 1 is a block diagram showing a configuration of televisionreceiver as an embodiment;

[0041]FIG. 2 is a diagram showing an example of a concept of a methodfor producing coefficient seed data;

[0042]FIG. 3 is a diagram showing a positional relationship between thepixels of the 525 i signal (the SD signal) and the pixels of the 1050 isignal (the HD signal);

[0043]FIG. 4 is a diagram for illustrating a phase shift in eight stagesin a vertical direction;

[0044]FIG. 5 is a diagram for illustrating a phase shift in four stagesin a horizontal direction;

[0045]FIG. 6 is a diagram showing a phase relationship between the SDsignal (the 525 i signal) and the HD signal (the 1050 i signal);

[0046]FIG. 7 is a block diagram showing an exemplary structure of acoefficient seed data production device;

[0047]FIG. 8 is a diagram of another example of a concept of a methodfor producing coefficient seed data;

[0048]FIG. 9 is a block diagram showing another exemplary structure of acoefficient seed data production device;

[0049]FIG. 10 is a block diagram showing an exemplary structure of animage signal processor to be implemented in software;

[0050]FIG. 11 is a flow chart showing a procedure of processing an imagesignal;

[0051]FIG. 12 is a flow chart showing a processing of producingcoefficient seed data (No. 1);

[0052]FIG. 13 is a flow chart showing a processing of producingcoefficient seed data (No. 2);

[0053]FIG. 14 is a diagram showing a positional relationship between thepixels of the 525 i signal and the pixels of the 1080 i signal;

[0054]FIG. 15 is a diagram showing a phase relationship in a verticaldirection between the pixels of the 525 i signal and the pixels of the1080 i signal;

[0055]FIG. 16 is a diagram showing a phase relationship in a horizontaldirection between the pixels of the 525 i signal and the pixels of the1080 i signal;

[0056]FIG. 17 is a diagram showing a positional relationship between thepixels of the 525 i signal and the pixels of the XGA signal;

[0057]FIG. 18 is a diagram showing a phase relationship in a verticaldirection between the pixels of the 525 i signal and the pixels of theXGA signal; and

[0058]FIG. 19 is a diagram showing a phase relationship in a horizontaldirection between the pixels of the 525 i signal and the pixels of theXGA signal.

BEST MODE FOR CARRYING OUT THE INVENTION

[0059] Hereinafter, embodiments of the present invention will bedescribed with reference to drawings. FIG. 1 shows a configuration oftelevision receiver 100 as an embodiment. The television receiver 100receives a 525 i signal from a broadcast signal and converts the 525 isignal into a 1080 i signal or a XGA signal so as to display an image,or converts the 525 i signal into a new 525 i signal for partiallymagnifying the image by an arbitrary magnification and displaying thepartially magnified image.

[0060] The television receiver 100 comprises a system controller 101with a microcomputer for controlling operations of the entire system,and a remote control signal receiving circuit 102 for receiving a remotecontrol signal. The remote control signal receiving circuit 102 isconnected to the system controller 101, and it is constituted so as toreceive a remote control signal RM from a remote control transmitter 200in accordance with the user operation and to supply an operation signalcorresponding to the received signal RM to the system controller 101.

[0061] The television receiver 100 also comprises a receiving antenna105, a tuner 106 for receiving a broadcast signal (RF modificationsignal) captured by the receiving antenna 105, and performing processingsuch as a channel selection, a middle frequency amplification, and awave detection so as to obtain a 525 i signal, and a buffer memory 109for temporarily storing the 525 i signal output from the tuner 106.

[0062] The television receiver 100 further comprises an image signalprocessing section 110 for using the 525 i signal temporarily stored inthe buffer memory 109 as an input image signal Vin and converting the525 i signal into a 1080 i signal or a XGA signal, or converting it intoa new 525 i signal for partially magnifying the image by an arbitrarymagnification and displaying the partially magnified image, and thentransmitting the resultant signal, and a display section 111 fordisplaying an image produced by the output image signal Vout receivedfrom the image signal processing section 110. The display section 111 isconstituted by, for example, a display apparatus such as a cathode-raytube (CRT) display, a liquid crystal display (LCD).

[0063] An operation of the television receiver 100 shown in FIG. 1 willbe described.

[0064] The 525 i signal transmitted from the tuner 106 is supplied tothe buffer memory 109, which temporarily stores it. The 525 i signalstored in the buffer memory 109 is supplied to the image signalprocessing section 110 as an input image signal Vin.

[0065] In the image signal processing section 110, in response to thesetting by the user through operations of the remote control transmitter200, the 525 i signal as the input image signal Vin is converted into a1080 i signal or a XGA signal, or the 525 i signal is converted into anew 525 i signal for partially magnifying the image by an arbitrarymagnification and displaying the partially magnified image. The outputimage signal Vout transmitted from the image signal processing section110 is supplied to the display section 111, which displays an imageproduced by the output image signal Vout on the screen thereof.

[0066] Next, details of the image signal processing section 110 will bedescribed. The image signal processing section 110 includes first tothird tap selection circuits 121 to 123 each for selectively extractinga plurality of pixel data located in periphery of each pixel (targetpixel) within a unit pixel block constituting the output image signalVout from the 525 i signal stored in the buffer memory 109, and thentransmitting them.

[0067] The first tap selection circuit 121 selectively extracts data ofthe pixel for use in prediction (hereinafter, referred to as “predictiontap”). The second tap selection circuit 122 selectively extracts data ofthe pixel for use in sorting space classes (hereinafter, referred to as“space class tap”). The third tap selection circuit 123 selectivelyextracts data of pixel for use in sorting movement classes (hereinafter,referred to as “movement class tap”). Where the space class isdetermined using the pixel data belonging to the plural fields, thisspace class also contains information about movements.

[0068] The image signal processing section 110 also includes a spaceclass detection circuit 124 for detecting a distribution pattern oflevels of data of space class tap (two or more) selectively extracted inthe second tap selection circuit 122, and detecting a space class basedon the distribution pattern of the levels so as to transmit informationabout the class.

[0069] The space class detection circuit 124 performs an operation suchthat, for example, the space class tap data is compressed from 8bit-data into 2 bit-data. Then, the space class detection circuit 124transmits the compressed data each corresponding to the space class tapdata as class information of the space class. In this embodiment, datacompression is performed according to an adaptive dynamic range coding(ADRC) method. Alternative to ADRC, as a method for compressinginformation, also employable is prediction coding such as differentialpulse code modulation (DPCM), vector quantization (VQ) and the like.

[0070] Originally, ADRC is an adaptive re-quantization method, which hasbeen developed for use in high performance coding for video taperecorder (VTR). The ADRC is also preferable to a case used in the datacompression described above because this method is capable ofeffectively expressing a local pattern of a signal level in a shortlanguage. In the case of employing ADRC, defining the maximum value ofthe space class tap data as MAX, the minimum value thereof as MIN, adynamic range of the space class tap data as DR (=MAX−MIN+1), andre-quantized bit number as P, a re-quantized code qi as compressed datais obtained from an operation in following Equation (1) as to each spaceclass tap data ki.

qi=[(ki−MIN+0.5).2^(P) /DR]  (1)

[0071] In the Equation (1), the portion enclosed with [ ] meanstruncation process. When there is pixel data in the number of Na as thespace class tap data, i is set to 1 to Na.

[0072] The image signal processing section 110 also includes an movementclass detection circuit 125 for detecting a movement class for mainlyexpressing the degree of movement, from the movement class tap data (twoor more) selectively extracted in the third tap selection circuit 123,and then transmitting the class information thereof.

[0073] In the movement class detection circuit 125, a differentialbetween frames is calculated from the movement class tap dataselectively extracted in the third tap selection circuit 123. Then, athreshold value processing is performed on an average value of theabsolute values of differentials so that the movement class, which is anindex of movement, can be detected. Specifically, in the movement classdetection circuit 125, an average value AV of the absolute values of thedifferentials is calculated in following Equation (2). $\begin{matrix}{{AV} = \frac{\sum\limits_{i = 1}^{Nb}{{{mi} - {ni}}}}{Nb}} & (2)\end{matrix}$

[0074] When six pixel data m1 to m6 and six pixel data n1 to n6 locatedin the immediately preceding frame are extracted as class tap data, forexample, in the third tap selection circuit 123, Nb in the Equation (2)is 6.

[0075] In the movement class detection circuit 125, the average value AVcalculated as described above is compared with one or a plurality ofthreshold values so as to allow class information MV about movementclass to be obtained. For example, when three threshold values th1, th2,th3 (th1<th2<th3) are prepared and four movement classes are to bedetected, MV is set to 0 when AV≦th1; MV is set to 1 when th1<AV≦th2; MVis set to 2 when th2<AV≦th3; and MV is set to 3 when th3<AV.

[0076] The image signal processing section 110 also includes a classsynthesis circuit 126 for obtaining a class code CL showing a classincluding the data of each pixel (target pixel) within the unit pixelblock constituting the output image signal Vout to be produced, based onthe re-quantized code qi as class information about the space classreceived from the space class detection circuit 124 and the classinformation MV about the movement class received from the movement classdetection circuit 125.

[0077] In the class synthesis circuit 126, the class code CL iscalculated in following Equation (3). $\begin{matrix}{{CL} = {{\sum\limits_{i\quad 1}^{Na}{{qi}\left( 2^{P} \right)}^{i\quad 1}} + {{MV} \cdot \left( 2^{P} \right)^{Na}}}} & (3)\end{matrix}$

[0078] In the Equation (3), Na indicates the number of space class tapdata, and P indicates the re-quantized bit number in ADRC method.

[0079] The image signal processing section 110 also includes registers130 to 133 and a coefficient memory 134. A post-processing circuit 129,which will be described later, is required to change its operation amongthe case where a 1080 i signal is transmitted as the output image signalVout, the case where an XGA signal is transmitted as the output imagesignal Vout, and the case where a 525 i signal is transmitted as theoutput image signal Vout. The register 130 stores operation specifyinginformation for specifying operations of the post-processing circuit129. The post-processing circuit 129 exhibits the operations incompliance with the operation specifying information supplied from theregister 130.

[0080] The register 131 stores information about the tap position of theprediction tap to be selected in the first tap selection circuit 121.The first tap selection circuit 121 selects the prediction tap incompliance with the tap position information supplied from the register131. The tap position information assigns numbers to the plurality ofpixels which may be selected for example, and specifies the number ofpixel to be selected. The tap position information described hereinafteralso performs the same operation as described above.

[0081] The register 132 stores tap position information of the spaceclass tap to be selected in the second tap selection circuit 122. Thesecond tap selection circuit 122 selects the space class tap incompliance with the tap position information supplied from the register132.

[0082] Therein, the register 132 stores tap position information A ofthe case where a movement is relatively small, and tap positioninformation B of the case where a movement is relatively large. Which ofthe tap position information A or B is to be supplied to the second tapselection circuit 122 is determined by the class information MV of themovement class transmitted from the movement class detection circuit125.

[0083] Specifically, if MV is 0 or MV is 1 because there is no movementor the movement is small, the tap position information A is supplied tothe second tap selection circuit 122. The space class tap selected inthe second tap selection circuit 122 is made to extend over pluralfields. Contrarily, if MV is 2 or MV is 3 because the movement isrelatively large, the tap position information B is supplied to thesecond tap selection circuit 122. Although not shown in the drawings,the space class tap selected in the second tap selection circuit 122 ismade to be only the pixel within the field where the pixel to beproduced is present.

[0084] Alternatively, it is also possible that the register 131described above also stores the tap position information of the casewhere the movement is relatively small and the tap position informationof the case where the movement is relatively large, so that the tapposition information to be supplied to the first tap selection circuit121 can be selected by the class information MV of the movement classtransmitted from the movement class detection circuit 125.

[0085] The register 133 stores the tap position information of themovement class tap to be selected in the third tap selection circuit123. The third tap selection circuit 123 selects a movement class tap incompliance with the tap position information supplied from the register133.

[0086] The coefficient memory 134 stores, for each class, thecoefficient data of the estimated equation to be used in an estimatedprediction calculation circuit 127, which will be described later. Thecoefficient data is information for converting the 525 i signal into the1080 i signal or the XGA signal, or for converting the 525 i signal intoa new 525 i signal for partially magnifying the image by an arbitrarymagnification and displaying the partially magnified image. Thecoefficient memory 134 receives the class code CL from the classsynthesis circuit 126 described above as read address information.Coefficient data corresponding to the class code CL is read out of thecoefficient memory 134, and thus read coefficient data is supplied tothe estimated prediction calculation circuit 127.

[0087] The image signal processing section 110 also includes aninformation memory bank 135. In the information memory bank 135,movement specifying information to be stored into the register 130 andthe tap position information to be stored in the registers 131 to 133are stored beforehand.

[0088] Herein, as the movement specifying information to be stored inthe register 130, first movement specifying information for operatingthe post-processing circuit 129 to transmit the 1080 i signal, secondmovement specifying information for operating the post-processingcircuit 129 to transmit the XGA signal, and third movement specifyinginformation for operating the post-processing circuit 129 to transmitthe 525 i signal, are stored beforehand in the information memory bank135.

[0089] The user can make selection among the first conversion method fortransmitting the 1080 i signal, the second conversion method fortransmitting the XGA signal, or the third conversion method fortransmitting the 525 i signal, by operating the remote controltransmitter 200. In the case of selecting the third conversion method,the user can further specify the magnification (the image size) of theimage to be displayed. The information memory bank 135 receives theselection information about the conversion method to be selected fromthe system controller 101. The information memory bank 135 loads thefirst, second, or third movement specifying information in compliancewith the received selection information into the register 130.

[0090] In the information memory bank 135, first tap positioninformation corresponding to the first conversion method (1080 i),second tap position information corresponding to the second conversionmethod (XGA), and third tap position information corresponding to thethird conversion method (525 i), are stored beforehand as the tapposition information of the prediction tap to be stored in the register131. The information memory bank 135 loads the first, second, or thirdtap position information into the register 131 in compliance with theselection information about the conversion method described above.

[0091] It is also possible that tap position information correspondingto the magnification of the image to be displayed is stored into theinformation memory bank 135 beforehand as the third tap positioninformation corresponding to the third conversion method, and at thesame time when the third conversion method is selected, the tap positioninformation corresponding to the specified magnification is loaded fromthe information memory bank 135 into the register 131. The same thing isapplicable to the case where the tap information is loaded intoregisters 132 and 133, which will be described later.

[0092] Further, the first tap position information corresponding to thefirst conversion method (1080 i), the second tap position informationcorresponding to the second conversion information (XGA), and the thirdtap position information corresponding to the third conversion method(525 i) are stored beforehand in the information memory bank 135 as tapposition information of the space class tap to be stored into theregister 132. The first, second, and third tap position information isrespectively constituted by tap position information for the case wherea movement is relatively small, and tap position information for thecase where a movement is relatively large. The first, second, or thirdtap position information is loaded from the information memory bank 135into the register 132 in compliance with the selection information aboutthe conversion method described above.

[0093] Further, the first tap position information corresponding to thefirst conversion method (1080 i), the second tap position informationcorresponding to the second conversion method (XGA), and the third tapposition information corresponding to the third conversion method (525i) are stored beforehand in the-information memory bank 135 as tapposition information of the movement class tap to be stored in theregister 133. The first, second, or third tap position information isloaded from the information memory bank 135 into the register 133 incompliance with the selection information about the conversion methoddescribed above.

[0094] Further, the information memory bank 135 stores coefficient seeddata of each class beforehand. The coefficient seed data is coefficientdata of the production equation for producing coefficient data to bestored into the coefficient memory 134 described above, the productionequation using the phase information as a parameter.

[0095] In the estimated prediction calculation circuit 127, which willbe described later, pixel data y to be produced is calculated accordingto the estimated equation of Equation (4) from prediction tap data xiand the coefficient data Wi read out of the coefficient memory 134.$\begin{matrix}{y = {\sum\limits_{i = 1}^{n}{{Wi} \cdot {xi}}}} & (4)\end{matrix}$

[0096] When ten prediction taps are selected in the first tap selectioncircuit 121, n in the Equation (4) is 10.

[0097] Then, the coefficient data Wi (i=1 to n) of this estimatedequation is produced according to the production equation using thephase information h, v as the parameter, as shown in following Equation(5) for example.

W ₁ =w ₁₀ +w ₁₁ v+w ₁₂ h+w ₁₃ v ² +w ₁₄ vh+w ₁₅ h ² +w ₁₆ v ³ +w ₁₇ v ²h+w ₁₈ vh ² +w ₁₉ h ³

W ₂ =w ₂₀ +w ₂₁ v+w ₂₂ h+w ₂₃ v ² +w ₂₄ vh+w ₂₅ h ² +w ₂₆ v ³ +w ²⁷ v ²h+w ₂₈ vh ² +w ₂₉ h ³

.

.

.

W ₁ =w ₁₀ +w ₁₁ v+w ₁₂ h+w ₁₃ v ² +w ₁₄ vh+w ₁₅ h ² +w ₁₆ v ³ +w ₁₇ v ²h+w ₁₈ vh ² +w ₁₉ h ³

.

.

.

W _(n) =w _(n0) +w _(n1) v+w _(n2) h+w _(n3) v ² +w _(n4) vh+w _(n5) h ²+w _(n6) v ³ +w _(n7) v ² h+w _(n8) vh ² +w _(n9) h ³  (5)

[0098] In the information memory bank 135, coefficient seed data W₁₀ toW_(n9), which is coefficient data of this production equation, is storedper class. The method for producing the coefficient seed data will bedescribed later.

[0099] The image signal processing section 110 also includes acoefficient production circuit 136 for producing, for each class, thecoefficient data Wi (i=1 to n) of the estimated equation correspondingto the values of the phase information h, v according to the Equation(5) using the coefficient seed data of each class and each value of thephase information h, v. The coefficient seed data of each class isloaded into this coefficient production circuit 136 from the informationmemory bank 135. In addition, the phase information h, v in thehorizontal direction and the vertical direction of each pixel within theunit pixel block constituting the output image signal Vout generated ina phase information generation circuit 139, which will be describedlater, is supplied to the coefficient production circuit 136. Thecoefficient data Wi (i=1 to n) each corresponding to the phaseinformation h, v of each class produced in the coefficient productioncircuit 136 is stored in the coefficient memory 134 described above.

[0100] The image signal processing section 110 also includes a phaseinformation generation circuit 139 for generating the phase informationh, v in the horizontal direction and the vertical direction of eachpixel within the unit pixel block constituting the output image signalVout, based on the selection information about the conversion method andthe corresponding function information n/m relating to the number ofpixels in each field in the vertical direction and in the horizontaldirection in the input image signal Vin and the output image signal Voutcorresponding to the information for specifying the magnification, whichare received from the system controller 101. This phase informationgeneration circuit 139 is constituted by a ROM table, for example.

[0101] The phase information h, v in the horizontal direction and thevertical direction of each pixel generated in the phase informationgeneration circuit 139 is respectively associated with the pixel number(tap number) and then supplied to the coefficient production circuit136. The phase information generation circuit 139 generates the phaseinformation h, v corresponding to the respective odd and even fields ofthe input image signal Vin.

[0102] For example, when the first conversion method (1080 i) isselected, n/m is 9/4 as to the vertical direction, and n/m is 9/4 as tothe horizontal direction (see FIG. 14). As a result, the 9×9 pixel blockof the 1080 i signal as the output image signal Vout corresponds to the4×4 pixel block of the 525 i signal as the input image signal Vin. Inthis case, the unit pixel block constituting the output image signalVout is a 9×9 pixel block.

[0103] In this case, in the phase information generation circuit 139, asto each pixel within this 9×9 unit pixel block, a distance betweenpixels located at positions closest to each other in the verticaldirection (pixels at a shortest distance) is obtained among the pixelswithin the 4×4 pixel block of the 525 i signal described above, and theobtained value of the distance is used as phase information v; and adistance between pixels located at positions closest to each other inthe horizontal direction (pixels at a shortest distance) is obtained,and the obtained value of the distance is used as phase information h.In this embodiment, the phase information h, v described above isobtained under the condition where the interval between pixels in thevertical direction of the 525 i signal is set to 16, and the intervalbetween pixels in the horizontal direction thereof is set to 8. The samething is applied to the case where the second and third conversionmethods are selected respectively.

[0104] Herein, the phase information v is set to a negative value whenthe target pixel within the 9×9 unit pixel block is located at aposition upper than the pixel at the shortest distance. Contrarily, thephase information v is set to a positive value when the target pixelwithin the 9×9 unit pixel block is located at a position lower than thepixel at the shortest distance described above. In addition, the phaseinformation h is set to a negative value when the target pixel thereofis located at a position left of the pixel at the shortest distance.Contrarily, the phase information h is set to a positive value when thetarget pixel thereof is located at a position right of the pixel at theshortest distance. The same thing is applied to the case where thesecond and third conversion methods are selected, respectively.

[0105] As described above, when the first conversion method (1080 i) isselected, in the phase information generation circuit 139, the phaseinformation h, v is generated for each of 81 pixels, which constitutethe 9×9 unit pixel block, in correspondence with the respective odd andeven fields.

[0106] In addition, when the second conversion method (XGA) is selectedfor example, n/m is 16/5 as to the vertical direction, and n/m is 8/5 asto the horizontal direction (see FIG. 17). As a result, the 8×16 pixelblock of the XGA signal as the output image signal Vout corresponds tothe 5×5 pixel block of the 525 i signal as the input image signal Vin.In this case, the unit pixel block constituting the output image signalVout is a 8×16 pixel block.

[0107] In this case, in the phase information generation circuit 139, asto each pixel within this 8×16 unit pixel block, a distance betweenpixels located at positions closest to each other in the verticaldirection (pixels at a shortest distance) is obtained among the pixelswithin the 5×5 pixel block of the 525 i signal described above, and theobtained value of the distance is used as phase information v; and adistance between pixels located at positions closest to each other inthe horizontal direction (pixels at a shortest distance) is obtained,and the obtained value of the distance is used as phase information h.

[0108] As described above, when the second conversion method (XGA) isselected, in the phase information generation circuit 139, the phaseinformation h, v is generated for each of 128 pixels, which constitutethe 8×16 unit pixel block, in correspondence with the respective odd andeven fields.

[0109] In addition, when the third conversion method (525 i) is selectedfor example, the values of n/m in the vertical direction and in thehorizontal direction are uniquely determined in correspondence with thespecified magnification of the image to be displayed (the image size).Assuming that n/m is nv/mv as to the vertical direction and n/m is nh/mhas to the horizontal direction, nh×nv pixel block of the 525 i signal asthe output image signal Vout corresponds to the mh×mv pixel block of the525 i signal as the input image signal Vin. In this case, the unit pixelblock constituting the output image signal Vout is a nh×nv pixel block.

[0110] In this case, in the phase information generation circuit 139, asto each pixel within this nh×nv unit pixel block, a distance betweenpixels located at positions closest to each other in the verticaldirection (pixels at a shortest distance) is obtained among the pixelswithin the mh×mv pixel block of the 525 i signal as the input imagesignal Vin described above, and the obtained value of the distance isused as phase information v; and a distance between pixels located atpositions closest to each other in the horizontal direction (pixels at ashortest distance) is obtained, and the obtained value of the distanceis used as phase information h.

[0111] As described above, when the third conversion method (525 i) isselected, in the phase information generation circuit 139, the phaseinformation h, v is generated for each of the pixels, which constitutethe nh×nv unit pixel block, in correspondence with the respective oddand even fields.

[0112] The image signal processing section 110 also includes anormalized coefficient production circuit 137 for calculating accordingto following Equation (6) a normalized coefficient S corresponding tothe coefficient data Wi (i=1 to n) of the respective phase informationh, v of each class produced by the coefficient production circuit 136,and a normalized coefficient memory 138 for storing thus-producednormalized coefficient S per class. The normalized coefficient memory138 receives the class code CL from the aforementioned class synthesiscircuit 126 as read address information. The normalized coefficient Scorresponding to the class code CL is read out of the normalizedcoefficient memory 138, and then thus read normalized coefficient S issupplied to a normalized calculation circuit 128, which will bedescribed later. $\begin{matrix}{S = {\sum\limits_{i = 1}^{n}{Wi}}} & (6)\end{matrix}$

[0113] The image signal processing section 110 also includes theestimated prediction calculation circuit 127 for calculating data ofeach pixel within the unit pixel block constituting the output imagesignal Vout, based on the prediction tap data xi selectively extractedin the first tap selection circuit 121 and the coefficient data Wi readout of the coefficient memory 134.

[0114] In this estimated prediction calculation circuit 127, pixel dataconstituting the output image signal Vout is produced for every unitpixel block. Specifically, the estimated prediction calculation circuit127 receives the prediction tap data xi corresponding to each pixelwithin the unit pixel block (target pixel) from the first tap selectioncircuit 121 and the coefficient data Wi corresponding to each pixelconstituting the unit pixel block from the coefficient memory 134. Thedata of each pixel constituting the unit pixel block is calculatedseparately according to the estimated equation of the aforementionedEquation (4).

[0115] For example, in the estimated prediction calculation circuit 127,when the first conversion method (1080 i) is selected, data of 81 pixelsconstituting the unit pixel block is simultaneously produced; when thesecond conversion method (XGA) is selected, data of 128 pixelsconstituting the unit pixel block is simultaneously produced; and whenthe third conversion method (525 i) is selected, data of pixels in thenumber of (nh×nv) constituting the unit pixel block (the values of nhand nv change in accordance with the specified magnification of theimage to be displayed) is simultaneously produced.

[0116] The image signal processing section 110 also includes anormalized calculation circuit 128 for normalizing with dividing thedata y₁ to y_(p) (P shows the number of pixels constituting the unitblock) of each pixel within the unit pixel block constituting the outputimage signal Vout, each data y₁ to y_(p) being sequentially output fromthe estimated prediction calculation circuit 127, by the normalizedcoefficient S corresponding to the coefficient data Wi (i=1 to n) whichis read from the normalized coefficient memory 138 and is used in theproduction of the respective data y₁ to y_(p). Although not describedabove, when the coefficient production circuit 136 produces thecoefficient data of the estimated equation from the coefficient seeddata according to the production equation, the produced coefficient datacontains a rounding error, and there is no guarantee that the sum of thecoefficient data Wi (i=1 to n) is 1.0. Therefore, the data y₁ to y_(p)of each pixel calculated in the estimated prediction calculation circuit127 involves a level fluctuation as a result of rounding error. Asdescribed above, the fluctuation can be removed by normalizing them inthe normalized calculation circuit 128.

[0117] In addition, the image signal processing section 110 alsoincludes the post-processing circuit 129 for processing the data y₁′ toy_(p)′ of the pixels within the unit pixel block normalized in thenormalized calculation circuit 128 and sequentially received therefrom,and transmitting the output image signal Vout with the format specifiedby any one of the first to third conversion methods. Specifically, thepost-processing circuit 129 transmits the 1080 i signal when the firstconversion method is selected, transmits the XGA signal when the secondconversion method is selected, and transmits the 525 i signal when thethird conversion method is selected. The information for specifying theoperation of the post-processing circuit 129 is supplied from theregister 130 as described above.

[0118] Next, an operation of the image signal processing section 110will be described.

[0119] In the second tap selection circuit 122, space class tap data(pixel data) located in periphery of each pixel (target pixel) withinthe unit pixel block constituting the output image signal Vout to beproduced is selectively extracted from the 525 i signal stored in thebuffer memory 109 as the input image signal Vin. In this case, in thesecond tap selection circuit 122, the selection of tap is performed,based on the conversion method supplied from the register 132 andselected by the user, and the tap position information corresponding tothe movement class detected in the movement class detection circuit 125.

[0120] Thus-obtained space class tap data is supplied to the space classdetection circuit 124. In the space class detection circuit 124, eachpixel data as the space class tap data is subjected to an ADRCprocessing so that a re-quantized code qi as class information of thespace class (a class sort mainly for the purpose of expressing thewaveform in a space) may be obtained (see the Equation (1)).

[0121] In addition, in the third tap selection circuit 123, movementclass tap data (pixel data) located in periphery of the pixels withinthe unit pixel block (target pixel) constituting the output image signalVout to be produced is selectively extracted from the 525 i signalstored in the buffer memory 109 as the input image signal Vin. In thiscase, in the third tap selection circuit 123, the selection of tap isperformed on the basis of the tap position information selected by theuser and supplied from the register 133, the tap position informationcorresponding to the conversion method.

[0122] Thus-obtained movement class tap data is supplied to the spaceclass detection circuit 125. According to the movement class detectioncircuit 125, class information MV about a movement class (a class sortmainly for the purpose of expressing the degree of movement) is obtainedfrom each pixel data as movement class tap data.

[0123] Thus-obtained movement information MV and the aforementionedre-quantized code qi are supplied to the class synthesis circuit 126. Inthe class synthesis circuit 126, a class code CL showing a classincluding data of each pixel within a unit pixel block (target pixel) isobtained from the movement information MV and the re-quantized code qi,as to each unit pixel block constituting the output image signal Vout tobe produced (see the Equation (3)). Then, thus-obtained class code CL issupplied to the coefficient memory 134 and the normalized coefficientmemory 138 as read address information.

[0124] The coefficient production circuit 136 produces coefficient dataWi (i=1 to n) of the estimated equation in each class corresponding tothe phase information h, v of each pixel within the unit pixel blockconstituting the output image signal Vout generated in the phaseinformation generation circuit 139, and then the coefficient data Wi isstored in the coefficient memory 134. In addition, the normalizedcoefficient production circuit 137 produces normalized coefficient Scorresponding to the coefficient data Wi (i=1 to n) in each class and ineach phase information produced by the coefficient production circuit136 as described above, and then the normalized coefficient S is storedin the normalized coefficient memory 138.

[0125] When the class code CL is supplied as read address information tothe coefficient memory 134 as described above, the coefficient data Wiin each phase information corresponding to the class code CL is read outof the coefficient memory 134 and then thus read coefficient data Wi issupplied to the estimated prediction calculation circuit 127. Inaddition, in the first tap selection circuit 121, prediction tap data(pixel data) located in periphery of each pixel (target pixel) withinthe unit pixel block constituting the output image signal Vout to beproduced is selectively extracted from the 525 i signal stored in thebuffer memory 109 as the input image signal Vin. In this case, in thefirst tap selection circuit 121, the selection of tap is performed onthe basis of the tap position information corresponding to theconversion method selected by the user and supplied from the register131. The prediction tap data xi is supplied to the estimated predictioncalculation circuit 127.

[0126] In the estimated prediction calculation circuit 127, data y₁ toy_(p) of each pixel within the unit pixel block constituting the outputimage signal Vout to be produced is simultaneously calculated, from theprediction tap data xi and the, coefficient data Wi in each phaseinformation read out of the coefficient memory 134 (see the Equation(4)). The data y₁ to y_(p) of each pixel within the unit pixel blockconstituting the output image signal Vout and sequentially transmittedfrom the estimated prediction calculation circuit 127, is supplied tothe normalized calculation circuit 128.

[0127] As described above, the class code CL is supplied to thenormalized coefficient memory 138 as read address information. Out ofthe normalized coefficient memory 138, read is the normalizedcoefficient S corresponding to the class code CL, that is, thenormalized coefficient S corresponding to the coefficient data Wi whichhas been used in calculating the data y₁ to y_(p) output from theestimated prediction calculation circuit 127. Thus read normalizedcoefficient S is supplied to the normalized calculation circuit 128. Inthe normalized calculation circuit 128, the data y₁ to y_(p) transmittedfrom the estimated prediction calculation circuit 127 is normalized withdividing them by their respectively corresponding normalizedcoefficients S. This removes the level fluctuation of the data y₁ toy_(p) caused by rounding error occurred when the coefficient data of theestimated equation (see the Equation (4)) is obtained according to theproduction equation (see the Equation (5)) using the coefficient seeddata.

[0128] The data y₁′ to y_(p)′ of each pixel within the unit pixel block,which is normalized in the normalized calculation circuit 128 andsequentially transmitted therefrom, is supplied to the post-processingcircuit 129. The post-processing circuit 129 receives the data y₁′ toy_(p)′ and transmits them with a format specified by any one of thefirst to third conversion methods as the output image signal Vout. Whenthe first conversion method is selected, the 1080 i signal istransmitted as the output image signal Vout. When the second conversionmethod is selected, the XGA signal is transmitted as the output imagesignal Vout. Further, when the third conversion method is selected, the525 i signal is transmitted as the output image signal Vout.

[0129] As described above, in the coefficient production circuit 136,coefficient data Wi of the estimated equation corresponding to thevalues of the phase information h, v is produced per class using thecoefficient seed data in each class loaded from the information memorybank 135 and the values of the phase information h, v generated in thephase information generation circuit 139. Then, the resultantcoefficient data Wi is stored into the coefficient memory 134. Then, byuse of the coefficient data Wi in each phase information read out of thecoefficient memory 134 in correspondence with the class code CL, thedata y₁ to y_(p) of each pixel within the unit pixel block constitutingthe output image signal Vout is calculated in the estimated predictioncalculation circuit 127. Consequently, this eliminates needs of a memoryfor storing a large amount of coefficient data when a format conversioninto the 1080 i signal or the XGA signal is performed, or a conversioninto various image sizes is performed.

[0130] As described above, the coefficient seed data is stored per classin the information memory bank 135. This coefficient seed data isproduced beforehand by learning.

[0131] First, an example of this production method will be described.The description will be made as to an example where coefficient seeddata w₁₀ to w_(n9), which is coefficient data in the production equationof the Equation (5), should be obtained.

[0132] Herein, the terms ti (i=0 to 9) are defined as following Equation(7), for the purpose of description:

t ₀=1; t ₁ =v; t ₂ =h; t ₃ =v ² ; t ₄ =vh; t ₅ =h ² ; t ₆ =v ³ ; t ₇ =v² h; t ₈ =vh ²; and t ₉ =h ³  (7)

[0133] By use of the Equation (7) above, the Equation (5) can berewritten into Equation (8) as follows. $\begin{matrix}{W_{i} = {\sum\limits_{j = 0}^{9}{w_{ij}t_{i}}}} & (8)\end{matrix}$

[0134] Finally, an undefined coefficient w_(ij) is obtained by theleaning. Specifically, this is a solution method by use of a leastsquare method where a coefficient value which minimizes a square erroris defined per class using pixel data of a student signal and pixel dataof a teacher signal. Defining the number of learning as m, a residualerror at k-th learning data (1≦k≦m) as e_(k), and a sum of square errorsas E, E is expressed in following Equation (9) by use of the Equations(4) and (5). $\begin{matrix}\begin{matrix}{E = \quad {\sum\limits_{k = 1}^{m}e_{k}^{2}}} \\{= \quad {\sum\limits_{k = 1}^{m}\left( \left\lbrack {y_{k} - \left( {{W_{1}x_{1K}} + {W_{2}x_{2K}} + \ldots + {W_{n}x_{nK}}} \right)} \right\rbrack \right)^{2}}} \\{= \quad {\sum\limits_{k = 1}^{m}\left\{ {y_{k} - \left\lbrack {{\left( {{t_{0}w_{10}} + {t_{1}w_{11}} + \ldots + {t_{9}w_{19}}} \right)x_{1k}} + \ldots +} \right.} \right.}} \\\left( \left. {\quad \left. {\left( {{t_{0}w_{n0}} + {t_{1}w_{n1}} + \ldots + {t_{9}w_{n9}}} \right)x_{nk}} \right\rbrack} \right\} \right)^{2} \\{= \quad {\sum\limits_{k = 1}^{m}\left\{ {y_{k} - \left\lbrack {{\left( {w_{10} + {w_{11}v} + \ldots + {w_{19}h^{3}}} \right)x_{1k}} + \ldots +} \right.} \right.}} \\\left( \left. {\quad \left. {\left( {w_{n0} + {w_{n1}v} + \ldots + {w_{n9}h^{3}}} \right)x_{nk}} \right\rbrack} \right\} \right)^{2}\end{matrix} & (9)\end{matrix}$

[0135] Herein, the term x_(lk) shows k-th pixel data at a position ofi-th prediction tap of the student image, and the term y_(k) shows k-thpixel data of the teacher image corresponding thereto.

[0136] In the solution method by use of the least square method, a valueof w_(lj) which makes the partial differentiation of the Equation (9)into 0 is obtained. This is expressed by Equation (10) as follows.$\begin{matrix}{\frac{\partial E}{\partial w_{ij}} = {{\sum\limits_{k = 1}^{m}{2\left( \frac{\partial e_{k}}{\partial w_{ij}} \right)e_{k}}} = {{- {\sum\limits_{k = 1}^{m}{2t_{j}x_{1k}e_{k}}}} = 0}}} & (10)\end{matrix}$

[0137] Hereinafter, defining the terms X_(lpjq) and Y_(lp) as shown infollowing Equations (11) and (12), the Equation (10) can be rewritteninto following Equation (13) by use of matrix. $\begin{matrix}{X_{ipjq} = {\sum\limits_{k = 1}^{m}{x_{ik}t_{p}x_{jk}t_{q}}}} & (11) \\{Y_{ip} = {\sum\limits_{k = 1}^{m}{x_{ik}t_{p}y_{k}}}} & (12) \\{{\begin{bmatrix}X_{1010} & X_{1011} & X_{1012} & \cdots & X_{1019} & X_{1020} & \cdots & X_{10{n9}} \\X_{1110} & X_{1111} & X_{1112} & \cdots & X_{1119} & X_{1120} & \cdots & X_{11{n9}} \\X_{1210} & X_{1211} & X_{1212} & \cdots & X_{1219} & X_{1220} & \cdots & X_{12{n9}} \\\vdots & \vdots & \vdots & ⋰ & \vdots & \vdots & ⋰ & \vdots \\X_{1910} & X_{1911} & X_{1912} & \cdots & X_{1919} & X_{1920} & \cdots & X_{19{n9}} \\X_{2010} & X_{2011} & X_{2012} & \cdots & X_{2019} & X_{2020} & \cdots & X_{20{n9}} \\\vdots & \vdots & \vdots & ⋰ & \vdots & \vdots & ⋰ & \vdots \\X_{n910} & X_{n911} & X_{n912} & \cdots & X_{n919} & X_{n920} & \cdots & X_{n9n9}\end{bmatrix}\begin{bmatrix}w_{10} \\w_{11} \\w_{12} \\\vdots \\w_{19} \\w_{20} \\\vdots \\w_{n9}\end{bmatrix}} = \begin{bmatrix}Y_{10} \\Y_{11} \\Y_{12} \\\vdots \\Y_{19} \\Y_{20} \\\vdots \\Y_{n9}\end{bmatrix}} & (13)\end{matrix}$

[0138] This equation is generally referred to as a normal equation. Thenormal equation is solved about w_(lj) by use of a sweeping method(Gauss-Jordan elimination method) and the like so that coefficient seeddata can be calculated.

[0139]FIG. 2 shows a concept of the aforementioned method for producingthe coefficient seed data. An SD signal (525 i signal) as a studentsignal is produced from a HD signal (1050 i signal) as a teacher signal.

[0140]FIG. 3 shows a positional relationship of pixels between the 525 isignal and the 1050 i signal. Herein, large dots are pixels of the 525 isignal, and small dots are pixels of the 1050 i signal. Solid linesexpress the positions of pixels in odd fields, and broken lines expressthe positions of pixels in even fields.

[0141] The phase of this SD signal is shifted into eight stages in avertical direction, and is shifted into four stages in a horizontaldirection so that 8×2=16 kinds of SD signals SD₁ to SD₁₆ can beproduced. FIG. 4 shows the states of phase shifts V1 to V8 into eightstages in a vertical direction. Herein, the interval between pixels ofthe SD signal in the vertical direction is 16, and the downwarddirection is set to a positive direction. In addition, the term “o”expresses an odd field, and the term “e” expresses an even field.

[0142] In the state of V1, the shift amount of the SD signal is set to0. In this case, the pixels of the HD signal come to have phases of 4,0, −4, and −8 with respect to the pixels of the SD signal. In the stateof V2, the shift amount of the SD signal is set to 1. In this case, thepixels of the HD signal come to have phases of 7, 3, −1, and −5 withrespect to the pixels of the SD signal. In the state of V3, the shiftamount of the SD signal is set to 2. In this case, the pixels of the HDsignal come to have phases of 6, 2, −2, and −6 with respect to thepixels of the SD signal. In the state of V4, the shift amount of the SDsignal is set to 3. In this case, the pixels of the HD signal come tohave phases of 5, 1, −3, and −7 with respect to the pixels of the SDsignal.

[0143] In the state of V5, the shift amount of the SD signal is set to4. In this case, the pixels of the HD signal come to have phases of 4,0, −4, and −8 with respect to the pixels of the SD signal. In the stateof V6, the shift amount of the SD signal is set to 5. In this case, thepixels of the HD signal come to have phases of 7, 3, −1, and −5 withrespect to the pixels of the SD signal. In the state of V7, the shiftamount of the SD signal is set to 6. In this case, the pixels of the HDsignal come to have phases of 6, 2, −2, and −6 with respect to thepixels of the SD signal. In the state of V8, the shift amount of the SDsignal is set to 7. In this case, the pixels of the HD signal come tohave phases of 5, 1, −3, and −7 with respect to the pixels of the SDsignal.

[0144]FIG. 5 shows the states of phase shifts H1 to H4 into four stagesin a horizontal direction. Herein, the interval between pixels of the SDsignal in the horizontal direction is set to 8, and the right directionis set to a positive direction.

[0145] In the state of H1, the shift amount of the SD signal is set to0. In this case, the pixels of the HD signal come to have phases of 0,and −4 with respect to the pixels of the SD signal. In the state of H2,the shift amount of the SD signal is set to 1. In this case, the pixelsof the HD signal come to have 3, and −1 with respect to the pixels ofthe SD signal. In the state of H3, the shift amount of the SD signal isset to 2. In this case, the pixels of the HD signal come to have phasesof 2, and −2 with respect to the pixels of the SD signal. In the stateof H4, the shift amount of the SD signal is set to 3. In this case, thepixels of the HD signal come to have phases of 1, and −3 with respect tothe pixels of the SD signal.

[0146]FIG. 6 shows the phases of the pixels of the HD signal in a casewhere the pixels of the SD signal are located at center positions, as to32 kinds of SD signals obtained as a result of shifting the phase of theSD signal into 8 stages in the vertical direction and into 4 stages inthe horizontal direction as described above. In other words, the pixelsof the HD signal come to have phases expressed by  in FIG. 6 withrespect to the pixels of the SD signal.

[0147] Returning back to FIG. 2, learning is performed between each ofthe SD signals in 32 kinds in total obtained as a result of shifting itsphase into 8 stages in the vertical direction and into 4 stages in thehorizontal direction, and the HD signal, so that the coefficient seeddata can be produced.

[0148]FIG. 7 shows a configuration of a coefficient seed data productiondevice 150 for producing the coefficient seed data, based on the conceptdescribed above.

[0149] The coefficient seed data production device 150 includes an inputterminal 151 for receiving the HD signal (1050 i signal) as a teachersignal, an SD signal production circuit 152A for performing athinning-out processing on the HD signal in horizontal and verticaldirections so as to obtain the SD signal as an input signal, and a phaseshift circuit 152B for shifting the phase of the SD signal into 8 stagesin the vertical direction and into 4 stages in the horizontal directionso as to obtain the SD signals SD₁ to SD₃₂ in 32 kinds in total. Thephase shift circuit 152B receives parameters H, V for specifying thevalues of the phase shifts in the vertical direction and in thehorizontal direction. The phase shift circuit 152B is constituted by,for example, a filter having a characteristic of sinx/x; however, it isalso possible to employ another kind of filter which enables phaseshift. As an example of another kind of filter, there is a method whereonly a desired phase is extracted from an over sampling filter, or thelike.

[0150] The coefficient seed data production device 150 also includesfirst to third tap selection circuits 153 to 155 each for selectivelyextracting the data of a plurality of SD pixels located in periphery ofthe target position in the HD signal (1050 i signal) from the SD signalsSD₁ to SD₃₂ received from the phase shift circuit 152B, and thentransmits the extracted data.

[0151] These first to third tap selection circuits 153 to 155 areconstituted so as to have the same structures as those of the first tothird tap selection circuits 121 to 123 in the image signal processingsection 110 described above. The taps selected in the fist to third tapselection circuits 153 to 155 are specified by the tap positioninformation provided from a tap selection control section 156. Inaddition, the class information MV of the movement class output from amovement class detection circuit 158, which will be described later, issupplied to the tap selection control circuit 156. As a result of this,the tap position information to be supplied to the second tap selectioncircuit 154 is differed depending on whether a movement is large orsmall.

[0152] The coefficient seed data production apparatus 150 also includesa space class detection circuit 157 for detecting the distributionpattern of the levels of the space class tap data (SD pixel data)selectively extracted in the second tap selection circuit 154, detectinga space class based on the distribution pattern of levels, and thentransmitting the class information thereof. The space class detectioncircuit 157 is constituted so as to have the same structure as that ofthe space class detection circuit 124 in the image signal processingsection 110 described above. The space class detection circuit 157transmits, as class information showing the space class, a re-quantizedcode qi for each SD pixel data as the space class tap data.

[0153] The coefficient seed data production apparatus 150 also includesthe movement class detection circuit 158 for detecting a movement classmainly showing the degree of movement from the class tap data (SD pixeldata) selectively extracted in the third tap selection circuit 155, andthen transmitting the class information MV thereof. The movement classdetection circuit 158 is constituted so as to have the same structure asthat of the movement class detection circuit 125 in the image signalprocessing section 110 described above. In the movement class detectioncircuit 158, a differential between frames is calculated from themovement class tap data (SD pixel data) which is selectively extractedin the third tap selection circuit 155. Then, a threshold valueprocessing is performed on an average value of the absolute values ofdifferentials so that the movement class, which is an index of movement,can be detected.

[0154] The coefficient seed data production apparatus 150 also includesa class synthesis circuit 159 for obtaining a class code CL showing aclass including the pixel data at the target position in the HD signal(1050 i signal), based on the re-quantized code qi as class informationabout the space class received from the space class detection circuit157 and the class information MV about the movement class received fromthe movement class detection circuit 158. The class synthesis circuit159 is also constituted so as to have the same structure as that of theclass synthesis circuit 126 in the image signal processing section 110described above.

[0155] The coefficient seed data production apparatus 150 also includesa normal equation production section 160 for producing a normal equation(see the Equation (13)) to be employed for obtaining coefficient seeddata w₁₀ to w_(n9) for each class, from each HD pixel data y as pixeldata at the target position obtained from the HD signal received at theinput terminal 151, prediction tap data (SD pixel data) xi selectivelyextracted in the first tap selection circuit 153 respectively incorrespondence with each HD pixel data y, and the class code CL receivedfrom the class synthesis circuit 159 respectively in correspondence witheach HD pixel data y, and the parameters H, V of the phase shift valuesin the vertical direction and in the horizontal direction.

[0156] In this case, learning data is produced in combination of one HDpixel data y and the prediction tap pixel data in the number of ncorresponding to the HD pixel data y. The parameters H, V to be suppliedto the phase shift circuit 152B are sequentially changed so that 32kinds of SD signals SD, to SD₃₂ having gradually-charged phase shiftvalues can be sequentially produced. As a result, a normal equation inwhich a large number of learning data are registered is produced in thenormal equation production section 160. Thus, sequentially producing theSD signals SD₁ to SD₃₂ to register the learning data as described aboveallows the coefficient seed data for obtaining pixel data in anarbitrary phase to be obtained.

[0157] Although not shown in the drawings, when disposing a delaycircuit for time adjustment at a preceding stage of the first tapselection circuit 153, the timing of the SD pixel data xi supplied fromthe first tap selection circuit 153 to the normal equation productionsection 160 can be adjusted.

[0158] The coefficient seed data production apparatus 150 also includesa coefficient seed data decision section 161 for receiving data of thenormal equation produced for each class in the normal equationproduction section 160, and solving the normal equation for each classso as to obtain the coefficient seed data w₁₀ to w_(n9) in each class,and a coefficient seed memory 162 for storing thus-obtained coefficientseed data w₁₀ to w_(n9). In the coefficient seed data decision section161, the normal equation is solved according to a method such assweeping so that the coefficient data w₁₀ to w_(n9) can be obtained.

[0159] An operation of the coefficient seed data production apparatus150 shown in FIG. 7 will be described. When the input terminal 151receives an HD signal (1050 i signal) as a teacher signal, the HD signalis subjected to the thinning-out processing in horizontal and verticaldirections on the SD signal production circuit 152A so that an SD signal(525 i signal) as a student signal can be produced. Thus-produced SDsignal is supplied to the phase shift circuit 152B, which shifts thephase of the SD signal into 8 stages in the vertical direction and into4 stages in the horizontal direction (see FIGS. 4 and 5), so that 32kinds of SD signals SD₁ to SD₃₂ can be sequentially produced.

[0160] In the second tap selection circuit 154, space class tap data (SDpixel data) located in periphery of the target position in the HD signalis selectively extracted from these SD signals SD₁ to SD₃₂. In thesecond tap selection circuit 154, the selection of tap is performed,based on the tap position information supplied from the tap selectioncontrol circuit 156, the tap position information corresponding to themovement class detected in the movement class detection circuit 158.

[0161] The resultant space class tap data (SD pixel data) is supplied tothe space class detection circuit 157. In the space class detectioncircuit 157, each SD pixel data as the space class tap data is subjectedto ADRC processing so that a re-quantized code qi as class informationof the space class (a class sort mainly for the purpose of expressingthe waveform in a space) can be produced (see the Equation (1)).

[0162] In addition, in the third tap selection circuit 155, movementclass tap data (SD pixel data) located in periphery of the targetposition in the HD signal is selectively extracted from the SD signalsSD₁ to SD₃₂ obtained in the phase shift circuit 152B. In this case, inthe third tap selection circuit 155, the selection of the tap isperformed, based on the tap position information supplied from the tapselection control circuit 156.

[0163] Thus-obtained movement class tap data (SD pixel data) is suppliedto the movement class detection circuit 158. In the movement classdetection circuit 158, the class information MV about the movement class(a class sort mainly for the purpose of expressing the degree ofmovement) is obtained from each SD pixel data as movement class tapdata.

[0164] Thus-obtained movement information MV and the aforementionedre-quantized code qi are supplied to the class synthesis circuit 159. Inthe class synthesis circuit 159, the class code CL showing a classincluding pixel data at the target position in the HD signal is obtainedfrom the movement information MV and the re-quantized code qi (see theEquation (3)).

[0165] Further, in the first tap selection circuit 153, the predictiontap data (SD pixel data) located in periphery of the target position inthe HD signal is selectively extracted from the SD signals SD₁ to SD₃₂produced in the phase shift circuit 152B. In this case, in the first tapselection circuit 153, the selection of tap is performed, based on thetap position information supplied from the tap selection control circuit156.

[0166] In the normal equation production section 160, a normal equation(see the Equation (13)) to be employed for obtaining coefficient theseed data w₁₀ to w_(n9) is produced for each class, from each HD pixeldata y as pixel data at the target position obtained from the HD signalreceived at the input terminal 151, prediction tap data (SD pixel data)xi selectively extracted in the first tap selection circuit 153respectively in correspondence with each HD pixel data y, the class codeCL received from the class synthesis circuit 159 respectively incorrespondence with each HD pixel data y, and the parameters H, V of thephase shift values in the vertical direction and in the horizontaldirection.

[0167] Then, the normal equation is solved in the coefficient seed datadecision section 161 so that the coefficient seed data w₁₀ to w_(n9) foreach class can be obtained. The coefficient seed data w₁₀ to w_(n9) isstored in the coefficient seed memory 162 in which addresses areassigned for each class.

[0168] As described above, in the coefficient seed data productiondevice 150 shown in FIG. 7, it is possible to produce the coefficientseed data w₁₀ to w_(n9) for each class stored in the information memorybank 135 of the image signal processing section 110 shown in FIG. 1.

[0169] Next, another example of a method for producing the coefficientseed data will be described. In the following example, the descriptionwill be made as to an example where coefficient seed data w₁₀ to w_(n9),which is coefficient data in the production equation of the Equation(5), should be obtained.

[0170]FIG. 8 shows a concept of this example. As is the case of themethod for producing the coefficient seed data described above, the SDsignal is shifted into 8 stages in the vertical direction and is shiftedinto 4 stages into the horizontal direction by the parameters H, V, sothat 32 kinds of SD signals can be sequentially produced. Then, learningis performed between each SD signal and the HD signal so thatcoefficient data Wi of the estimated equation of the Equation (4) can beobtained. Then, coefficient seed data is produced using the coefficientdata Wi produced in correspondence with each SD signal.

[0171] First, a method for obtaining the coefficient data of theestimated equation will be described. Herein, a description will be madeas to a case where the coefficient data Wi (i=1 to n) of the estimatedequation of the Equation (4) is obtained using a least square method. Aconsideration will be made on an observation equation of followingEquation (14) as a generalized example, defining X as input data, W as acoefficient data, and Y as a predicted value. $\begin{matrix}\begin{matrix}{{XW} = \quad Y} \\{{X = \quad \begin{bmatrix}x_{11} & x_{12} & \cdots & x_{1n} \\x_{21} & x_{22} & \cdots & x_{2n} \\\cdots & \cdots & \cdots & \cdots \\x_{m1} & x_{m2} & \cdots & x_{mn}\end{bmatrix}},{W = \begin{bmatrix}W_{1} \\W_{2} \\\cdots \\W_{n}\end{bmatrix}},{Y = \begin{bmatrix}y_{1} \\y_{2} \\\cdots \\y_{m}\end{bmatrix}}}\end{matrix} & (14)\end{matrix}$

[0172] In the Equation (14), m expresses the number of learning data,and n expresses the number of prediction taps.

[0173] A least square method is applied to the data collected by use ofthe observation equation of the Equation (14). Based on the observationequation of the Equation (14), a residual equation of following Equation(15) is considered. $\begin{matrix}{{{XW} = {Y + E}},{E = \begin{bmatrix}e_{1} \\e_{2} \\\cdots \\e_{m}\end{bmatrix}}} & (15)\end{matrix}$

[0174] From the residual equation of the Equation (15), it is consideredthat the most probable value of each Wi is established when thecondition that minimizes the value of e² of following Equation (16) issatisfied. That is, the condition of following Equation (17) may beconsidered. $\begin{matrix}{e^{2} = {\sum\limits_{i = 1}^{m}e_{1}^{2}}} & (16) \\{{{e_{1}\frac{\partial e_{1}}{\partial w_{i}}} + {e_{2}\frac{\partial e_{2}}{\partial w_{i}}} + \ldots + {e_{m}\frac{\partial e_{m}}{\partial w_{i}}}} = {0\quad \left( {{i = 1},2,\ldots,n} \right)}} & (17)\end{matrix}$

[0175] Specifically, conditions in the number of n based on the value ofi of the Equation (17) are considered, and W₁, W₂, . . . W_(n) havingvalues satisfying these conditions may be obtained. As a result,following Equation (18) can be obtained from the residual equation ofthe Equation (15). Further, following Equation (19) can be also obtainedfrom the Equations (18) and (14). $\begin{matrix}{{\frac{\partial e_{1}}{\partial w_{1}} = x_{i1}},{\frac{\partial e_{1}}{\partial w_{2}} = x_{i2}},\ldots \quad,{\frac{\partial e_{1}}{\partial w_{n}} = {x_{in}\left( {{i = 1},2,\ldots \quad,m} \right)}}} & (18) \\{{{\sum\limits_{i = 1}^{m}{e_{1}x_{i1}}} = 0},{{\sum\limits_{i = 1}^{m}{e_{1}x_{i2}}} = 0},\ldots \quad,{{\sum\limits_{i = 1}^{m}{e_{1}x_{in}}} = 0}} & (19)\end{matrix}$

[0176] Then, a normal equation of following Equation (20) can beobtained from the Equations (15) and (19). $\begin{matrix}\left\{ \begin{matrix}{{{\left( {\sum\limits_{j = 1}^{m}{x_{j1}x_{j1}}} \right)w_{1}} + {\left( {\sum\limits_{j = 1}^{m}{x_{j1}x_{j2}}} \right)w_{2}} + \ldots + {\left( {\sum\limits_{j = 1}^{m}{x_{j1}x_{jn}}} \right)w_{n}}} = \left( {\sum\limits_{j = 1}^{m}{x_{j1}y_{j}}} \right)} \\{{{\left( {\sum\limits_{j = 1}^{m}{x_{j2}x_{j1}}} \right)w_{1}} + {\left( {\sum\limits_{j = 1}^{m}{x_{j2}x_{j2}}} \right)w_{2}} + \ldots + {\left( {\sum\limits_{j = 1}^{m}{x_{j2}x_{jn}}} \right)w_{n}}} = \left( {\sum\limits_{j = 1}^{m}{x_{j2}y_{j}}} \right)} \\\ldots \\{{{\left( {\sum\limits_{j = 1}^{m}{x_{jn}x_{j1}}} \right)w_{1}} + {\left( {\sum\limits_{j = 1}^{m}{x_{jn}x_{j2}}} \right)w_{2}} + \ldots + {\left( {\sum\limits_{j = 1}^{m}{x_{jn}x_{jn}}} \right)w_{n}}} = \left( {\sum\limits_{j = 1}^{m}{x_{jn}y_{j}}} \right)}\end{matrix} \right. & (20)\end{matrix}$

[0177] Since the normal equation of the Equation (20) is capable ofmaking equations in the same number as the unknown number n, the mostprobable value of each Wi can be obtained. In this case, simultaneousequations are solved by a method such as sweeping.

[0178] Next, a method for obtaining the coefficient seed data using thecoefficient data produced in correspondence with each SD signal will bedescribed.

[0179] It is assumed that coefficient data in a certain class, obtainedas a result of learning performed by use of the SD signal correspondingto the parameters H, V, is resulted into k_(vhi). Herein, the term iexpresses the prediction tap number. Coefficient seed data of this classis obtained from the k_(vhi).

[0180] Each coefficient data Wi (i=1 to n) is expressed in the Equation(5) described above using the coefficient seed data w₁₀ to w_(n9).Herein, under the consideration that a least square method is employedfor the coefficient data Wi, a residual is expressed by followingEquation (21). $\begin{matrix}\begin{matrix}{e_{vhi} = \quad {k_{vhi} - \left( {w_{i0} + {w_{i1}v} + {w_{i2}h} + {w_{i3}v^{2}} + {w_{i4}{vh}} + {w_{i5}h^{2}} +} \right.}} \\{\quad {{w_{i6}v^{3}} + {w_{i7}v^{2}h} + {w_{i8}{vh}^{2}} + {w_{i9}h^{3}}}} \\{= \quad {k_{vhi} - {\sum\limits_{j = 0}^{9}{w_{ij}t_{j}}}}}\end{matrix} & (21)\end{matrix}$

[0181] Herein, the term t_(j) has been expressed in the Equation (7)described above. When a least square method is employed in the Equation(21), following Equation (22) can be obtained. $\begin{matrix}\begin{matrix}{\frac{\partial}{\partial w_{ij}} = {{\sum\limits_{v}{\sum\limits_{h}\left( e_{vhi} \right)^{2}}} = {\sum\limits_{v}{\sum\limits_{h}{2\left( \frac{\partial e_{vhi}}{\partial w_{ij}} \right)e_{vhi}}}}}} \\{= {- {\sum\limits_{v}{\sum\limits_{h}{2t_{j}e_{vhi}}}}}} \\{= 0}\end{matrix} & (22)\end{matrix}$

[0182] Herein, defining the terms X_(jk), Y_(j) as following Equations(23) and (24) respectively, Equation (22) can be rewritten intofollowing $\begin{matrix}{X_{jk} = {\sum\limits_{v}{\sum\limits_{h}{t_{j}t_{k}}}}} & (23) \\{Y_{j} = {\sum\limits_{v}{\sum\limits_{h}{t_{j}k_{vhi}}}}} & (24) \\{{\begin{bmatrix}X_{00} & X_{01} & \cdots & X_{09} \\X_{10} & X_{11} & \cdots & X_{19} \\\vdots & \vdots & ⋰ & \vdots \\X_{90} & X_{91} & \cdots & X_{99}\end{bmatrix}\begin{bmatrix}w_{10} \\w_{11} \\\vdots \\w_{19}\end{bmatrix}} = \begin{bmatrix}Y_{0} \\Y_{1} \\\vdots \\Y_{9}\end{bmatrix}} & (25)\end{matrix}$

[0183] This Equation (25) is also a normal equation. By solving theEquation (25) according to a general solution such as a sweeping method,the coefficient seed data w₁₀ to w_(n9) can be obtained.

[0184]FIG. 9 shows a configuration of a coefficient seed data productiondevice 150′ for producing the coefficient seed data according to theconcept shown in FIG. 8. In FIG. 9, constituent elements correspondingto those of FIG. 7 are denoted by the same reference numerals, anddetailed descriptions thereof will be omitted.

[0185] The coefficient seed data production apparatus 150′ includes anormal equation production section 171 for producing a normal equation(see the Equation (20)) to be employed for obtaining coefficient data Wi(i=1 to n) for each class, from each HD pixel data y as target pixeldata obtained from the HD signal received at the input terminal 151,prediction tap data (SD pixel data) xi selectively extracted in thefirst tap selection circuit 153 respectively in correspondence with eachHD pixel data y, and the class code CL received from the class synthesiscircuit 159 respectively in correspondence with each HD pixel data y.

[0186] In this case, learning data is produced in combination of one HDpixel data y and the prediction tap pixel data in the number of ncorresponding to the HD pixel data y. The parameters H, V to be suppliedto the phase shift circuit 152B are sequentially changed so that 32kinds of SD signal SD₁ to SD₃₂ can be sequentially produced, thusproducing learning data between the HD signal and each SD signalrespectively. As a result, in the normal equation production section171, a normal equation for obtaining coefficient data Wi (i=1 to n) isproduced for each class in correspondence with each SD signal.

[0187] The coefficient seed data production apparatus 150′ also includesa coefficient data decision section 172 for receiving data of the normalequation produced in the normal equation production section 171, andsolving the normal equation so as to obtain coefficient data Wi for eachclass respectively corresponding to each SD signal, and a normalequation production section 173 for producing a normal equation (see theEquation (25)) for obtaining coefficient seed data w₁₀ to w_(n9) foreach class using the coefficient data Wi for each class respectivelycorresponding to each SD signal.

[0188] The coefficient seed data production apparatus 150′ also includesa coefficient seed data decision section 174 for receiving data of thenormal equation produced for each class in the normal equationproduction section 173 and the parameters H, V of the phase shift valuesin the vertical direction and in the horizontal direction, and solvingthe normal equation for each class so as to obtain coefficient seed dataw₁₀ to w_(n9) in each class, and a coefficient seed memory 162 forstoring thus-obtained coefficient seed data w₁₀ to w_(n9).

[0189] The remaining constituent elements of the coefficient seed dataproduction device 150′ shown in FIG. 9 have the same configuration asthat of the coefficient seed data production device 150 shown in FIG. 7.

[0190] An operation of the coefficient seed data production apparatus150′ shown in FIG. 9 will be described. An HD signal (1050 i signal) issupplied to the input terminal 151 as a teacher signal. Then, the HDsignal is subjected to the thinning-out processing in the horizontal andvertical directions in the SD signal production circuit 152A so that anSD signal (525 i signal) as a student signal can be obtained.Thus-produced SD signal is supplied to the phase shift circuit 152Bwhere the phase of the SD signal is shifted into 8 stages in thevertical direction and is shifted into 4 stages in the horizontaldirection (see FIGS. 4 and 5), so that 32 kinds of SD signals SD₁ toSD₃₂ are sequentially produced.

[0191] In the second tap selection circuit 154, space class tap data (SDpixel data) located in periphery of the target position in the HD signal(1050 i signal) is selectively extracted from these SD signals SD₁ toSD₃₂. In the second tap selection circuit 154, the selection of tap isperformed, based on the tap position information supplied from the tapselection control circuit 156, the tap position informationcorresponding to the movement class detected in the movement classdetection circuit 158.

[0192] The resultant space class tap data (SD pixel data) is supplied tothe space class detection circuit 157. In the space class detectioncircuit 157, each SD pixel data as the space class tap data is subjectedto ADRC processing so that a re-quantized code qi as class informationof the space class (a class sort mainly for the purpose of expressingthe waveform in a space) can be obtained (see the Equation (1)).

[0193] In addition, in the third tap selection circuit 155, movementclass tap data (SD image data) located in periphery of the targetposition in the HD signal is selectively extracted from the SD signalsSD₁ to SD₃₂ obtained in the phase shift circuit 152B. In this case, inthe third tap selection circuit 155, the selection of the tap isperformed, based on the tap position information supplied from the tapselection control circuit 156.

[0194] Thus-obtained movement class tap data (SD pixel data) is suppliedto the movement class detection circuit 158. In the movement classdetection circuit 158, class information MV about a movement class (aclass sort mainly for the purpose of expressing the degree of movement)is obtained from each SD pixel data as movement class tap data.

[0195] Thus-obtained movement information MV and the aforementionedre-quantized code qi are supplied to the class synthesis circuit 159. Inthe class synthesis circuit 159, a class code CL showing a classincluding pixel data at the target position in the HD signal is obtainedfrom the movement information MV and the re-quantized code qi (see theEquation (3)).

[0196] Further, in the first tap selection circuit 153, the predictiontap data (SD pixel data) located in periphery of the target position inthe HD signal is selectively extracted from the SD signals SD₁ to SD₃₂produced in the phase shift circuit 152B. In this case, in the first tapselection circuit 153, the selection of tap is performed, based on thetap position information supplied from the tap selection control circuit156.

[0197] In the normal equation production section 171, a normal equation(see the Equation (20)) to be employed for obtaining the coefficientdata Wi (i=1 to n) is produced for each class respectively incorrespondence with each SD signal produced in the SD signal productioncircuit 152, from each HD pixel data y as pixel data at the targetposition obtained from the HD signal received at the input terminal 151,prediction tap data (SD pixel data) xi selectively extracted in thefirst tap selection circuit 153 respectively in correspondence with eachHD pixel data y, and the class code CL receiving from the classsynthesis circuit 159 respectively in correspondence with each HD pixeldata y.

[0198] Then, the normal equation is solved in the coefficient datadecision section 172 so that coefficient data Wi for each classrespectively corresponding to each DS signal can be obtained. In thenormal equation production section 173, a normal equation (see theEquation (25)) employed for obtaining coefficient seed data W₁₀ tow_(n9) is produced for each class, from the coefficient data Wi for eachclass respectively corresponding to each SD signal and the parameters H,V of the phase shift values in the vertical direction and in thehorizontal direction.

[0199] Then, the normal equation is solved in the coefficient seed datadecision section 174 so that coefficient seed data w₁₀ to w_(n9) foreach class can be obtained. The coefficient seed data w₁₀ to w_(n9) isstored in the coefficient seed memory 162 in which addresses areassigned for each class.

[0200] As described above, in the coefficient seed data productiondevice 150′ shown in FIG. 9 as well, it is possible to produce thecoefficient seed data w₁₀ to w_(n9) for each class stored in theinformation memory bank 135 of the image signal processing section 110shown in FIG. 1.

[0201] In the image signal processing section 110 shown in FIG. 1, theproduction equation of the Equation (5) has been employed for producingthe coefficient data Wi (i=1 to n). Alternatively, it is also possibleto employ following Equation (26) or (27). Further alternatively, thecoefficient data Wi also can be produced by employing a polynomialequation of different degrees or an equation expressed by anotherfunction.

W ₁ =w ₁₀ +w ₁₁ v+w ₁₂ +h+w ₁₃ v ² +w ₁₄ h ² +w ₁₅ v ³ +w ₁₆ h ³

W ₂ =w ₂₀ +w ₂₁ v+w ₂₂ h+w ₂₃ v ² +w ₂₄ h ² +w ₂₅ v ³ +w ₂₆ h ³

.

.

.

W ₁ =w ₁₀ +w ₁₁ v+w ₁₂ h+w ₁₃ v ² +w ₁₄ h ² +w ₁₅ v ³ +w ₁₆ h ³

.

.

.

W _(n) =w _(n0) +w _(n1) v+w _(n2) h+w _(n3) v ² +w _(n4) h ² +w _(n5) v³ w _(n6) h ³  (26)

W ₁ =w ₁₀ +w ₁₁ v+w ₁₂ h+w ₁₂ h+w ₁₃ v ² +w ₁₄ vh+w ₁₅ h ²

W ₂ =w ₂₀ +w ₂₁ v+w ₂₂ h+w ₂₃ v ² +w ₂₄ vh+w ₂₅ h ²

.

.

.

W ₁ =w ₁₀ +w ₁₁ v+w ₁₂ h+w ₁₃ v ² +w ₁₄ vh+w ₁₅ h ²

.

.

.

W _(n) =w _(n0) +w _(n1) v+w _(n2) h+w _(n3) v ² +w _(n4) vh+w _(n5) h²  (27)

[0202] In addition, the processing performed in the image signalprocessing section 110 can be implemented in software, by use of animage signal processor such as the image signal processor 300 as shownin FIG. 10.

[0203] First, the image signal processor 300 shown in FIG. 10 will bedescribed. The image signal processor 300 comprises a CPU 301 forcontrolling operations of the entire apparatus, a ROM (Read Only Memory)302 for storing an operation program for the CPU 301, coefficient seeddata, and the like, and a RAM (Random Access Memory) 303 for organizinga working area for the CPU 301. The CPU 301, ROM 302 and RAM 303 areconnected to a bus 304, respectively.

[0204] The image signal processor 300 also comprises a hard disc drive(HDD) 305 as an external storage apparatus, and a disc drive (FDD) 307for driving a Floppy (Trade Name) disc 306. These drives 305, 307 areconnected to the bus 304, respectively.

[0205] The image signal processor 300 also comprises a communicationsection 308 for connecting to a communication network 400 such as theInternet through wired transmission or radio transmission. Thecommunication section 308 is connected to the bus 304 via an interface309.

[0206] The image signal processor 300 also comprises a user interfacesection. The user interface section includes a remote control signalreceiving circuit 310 for receiving a remote control signal RM from aremote control transmitter 200, and a display 311 constituted by aliquid crystal display (LCD) and the like. The receiving circuit 310 isconnected to the bus 304 via an interface 312, and similarly, thedisplay 311 is connected to the bus 304 via the interface 313.

[0207] The image signal processor 300 also comprises an input terminal314 for receiving a 525 i signal as an input image signal Vin, and anoutput terminal 315 for transmitting an output image signal Vout. Theinput terminal 314 is connected to the bus 304 via an interface 316, andsimilarly, the output terminal 315 is connected to the bus 304 via aninterface 317.

[0208] The processing program, the coefficient seed data and the likemay be, instead of being stored into the ROM 302 beforehand as describedabove, downloaded from the communication network 400 such as theInternet via the communication section 308 so as to be stored into thehard disc or the RAM 303, and then be used. Further, the processingprogram, the coefficient seed data and the like may be provided in thestate of being stored in the Floppy (Trade Name) disc 306.

[0209] Further, the 525 i signal as the input image signal Vin may be,instead of being received through the input terminal 314, recorded in ahard disc beforehand, or may be downloaded from the communicationnetwork 400 such as the Internet via the communication section 308. Inaddition, the output image signal Vout may be, instead of or at the sametime of being transmitted through the output terminal 315, supplied tothe display 311 so as to display an image. Alternatively, the outputimage signal Vout signal may be stored in a hard disc, or may betransmitted to the communication network 400 such as the Internet viathe communication section 308.

[0210] Referring to a flow chart of FIG. 11, a processing procedure forobtaining the output image signal Vout from an input image signal Vin inthe image signal processor 300 shown in FIG. 10 will be described.

[0211] First, a processing starts in Step ST1. Then, in Step ST2, inputimage signals Vin are input in the unit of frame or in the unit offield. If the input image signals Vin are input through the inputterminal 314, the RAM 303 temporarily stores the pixel data constitutingthe input image signal Vin. If the input image signals Vin are recordedon the hard disc, the input image signal Vin is read out of the harddisc drive 307 and then the RAM 303 temporarily stores the pixel dataconstituting the input image signal Vin. Then, in Step ST3, it is judgedwhether or not the processing of the input image signal Vin is finishedfor all frames or all fields. If the processing is finished, then theprocessing finishes in Step ST4. Contrarily, if the processing has notyet finished, then the procedure goes to Step ST5.

[0212] In Step ST5, phase information h, v about each pixel within theunit pixel block constituting the output image signal Vout is generatedusing the value of n/m in compliance with the conversion method(including the magnification of an image to be displayed) selected bythe user through operating the remote control transmitter 200. Then, inStep ST6, coefficient data Wi of the estimated equation (see theEquation (4)) for each class is produced corresponding to each pixelwithin the unit pixel block according to the production equation (forexample, the Equation (5)) using the phase information h, v about eachpixel within the unit pixel block and the coefficient seed data for eachclass.

[0213] Next, in Step ST7, class tap data and prediction tap pixel dataare obtained from the pixel data of the input image signal Vin input inStep ST2, in correspondence with each pixel data within the unit pixelblock constituting the output image signal Vout to be produced. Then, inStep ST8, it is judged whether or not the processing for obtaining thepixel data of the output image signal Vout finishes in all the areas ofthe input pixel data of the input image signal Vin. If the processingfinishes, then the procedure returns to the Step ST2 where the proceduregoes to a processing of inputting input image signal Vin in the nextframe or field. Contrarily, if the processing has not yet finished, thenthe procedure goes to Step ST9.

[0214] In Step ST9, a class code CL is produced from the pixel data ofthe class tap obtained in Step ST7. Then, in Step ST10, data of eachpixel within the unit pixel block constituting the output image signalVout is produced according to the estimated equation using thecoefficient data corresponding to the produced class code CL and the SDpixel data of the prediction tap. After that, the procedure returns tothe Step ST7 where the same processing as described above is repeated.

[0215] In the manner as described above, the pixel data of the inputimage signal Vin which has been input is processed by performing theprocessing in accordance with the flow chart shown in FIG. 11 so thatthe pixel data of the output image signal Vout can be obtained. Asdescribed above, the output image signal Vout obtained as a result ofthe processing is transmitted to the output terminal 315, or is suppliedto the display 311 to display an image produced thereby. Alternatively,the output image signal Vout is supplied to the hard disc drive 305 tobe recorded on the hard disc.

[0216] In addition, the processing in the coefficient seed dataproduction device 150 shown in FIG. 7 can be implemented in software,although an illustration of the processing device thereof is omittedfrom the drawings.

[0217] Referring to the flow chart of FIG. 12, a processing procedurefor producing coefficient seed data will be described.

[0218] First, a processing starts in Step ST21. Then, in Step ST22,phase shift values (for example, specified by parameters H, V) of the SDsignal to be used for learning are selected. Then, in Step ST23, it isjudged whether or not the learning has been completed for all the phaseshift values. If the learning has not yet completed for all the phaseshift values, then the procedure goes to Step ST24.

[0219] In the Step ST24, already-known HD pixel data is input in theunit of frame or field. Then, in Step ST25, it is judged whether or notthe processing has been completed for all the HD pixel data. If theprocessing is completed, then the procedure returns to the Step ST22wherein the next phase shift value is selected and the same processingas described above is repeated. Contrarily, if the processing has notyet completed, then the procedure goes to Step ST26.

[0220] In Step ST26, SD pixel data having a phase shifted by the phaseshift value selected in the Step ST22 is produced from the HD pixel datawhich have been input in the Step ST24. Then, in Step ST27, pixel dataof class tap and pixel data of prediction tap are obtained from the SDpixel data produced in the Step ST26, in correspondence with each HDpixel data input in the Step ST24. Then, in Step ST28, it is judgedwhether or not the learning has been completed for all the areas in theproduced SD pixel data. If the learning is completed, then the procedurereturns to the Step ST24 wherein the next HD pixel data is input and thesame processing as described above is repeated. Contrarily, if thelearning has not yet completed, then the procedure goes to Step ST29.

[0221] In the Step ST29, a class code CL is produced from the SD pixeldata of the class tap obtained in the Step ST27. Then, in Step ST30, anormal equation (see the Equation (13)) is produced. After that, theprocedure returns to the Step ST27.

[0222] If the learning is completed for all the phase shift values inthe Step ST23, then the procedure goes to Step ST31. In the Step ST31,the normal equation is solved by a method such as sweeping so that thecoefficient seed data for each class can be obtained. Then, in StepST32, thus-obtained coefficient seed data is stored in the memory. Afterthat, the processing finishes in Step ST33.

[0223] As described above, the coefficient seed data for each class canbe obtained in the same procedure as that employed in the coefficientseed data production device 150 shown in FIG. 7, through the processingalong the flow chart shown in FIG. 12.

[0224] In addition, the processing in the coefficient seed dataproduction device 150′ shown in FIG. 9 can be also implemented insoftware, although an illustration of the processing device thereof isomitted from the drawings.

[0225] Referring to the flow chart of FIG. 13, a processing procedurefor producing coefficient seed data will be described.

[0226] First, a processing starts in Step ST41. Then, in Step ST42,phase shift values (for example, specified by parameters H, V) of the SDsignal to be used for learning are selected. Then, in Step ST43, it isjudged whether or not a calculation processing for coefficient data hasbeen finished for all the phase shift values. If it has not yetfinished, then the procedure goes to Step ST44.

[0227] In the Step ST44, already-known HD pixel data is input in theunit of frame or field. Then, in Step ST45, it is judged whether or notthe processing has been completed for all the HD pixel data. If theprocessing has not yet completed, the procedure goes to Step ST46wherein SD pixel data having a phase shifted by the phase shift valueselected in the Step ST42 is produced from the HD pixel data which havebeen input in the Step ST44.

[0228] Then, in Step ST47, pixel data of class tap and pixel data ofprediction tap are obtained from the SD pixel data produced in the StepST46, in correspondence with each HD pixel data input in the Step ST44.Then, in Step ST48, it is judged whether or not the learning has beencompleted for all the areas in the produced SD pixel data. If thelearning is completed, then the procedure returns to the Step ST44wherein the next HD pixel data is input and the same processing asdescribed above is repeated. Contrarily, if the learning has not yetcompleted, then the procedure goes to Step ST49.

[0229] In the Step ST49, a class code CL is produced from the SD pixeldata of the class tap obtained in the Step ST47. Then, in Step ST50, anormal equation (see the Equation (20)) is produced to be used forobtaining coefficient data. After that, the procedure returns to theStep ST47.

[0230] If the processing is completed for all the HD pixel data in theStep ST45 described above, then the normal equation produced in the StepST 50 is solved by a method such as sweeping in Step ST 51 wherein thecoefficient data for each class can be obtained. After that, theprocedure returns to the Step ST42 wherein the next phase shift value isselected and the same processing as described above is repeated so thatcoefficient data corresponding to the next phase shift value for eachclass can be obtained.

[0231] If the coefficient data has been obtained for all the phase shiftvalues in the Step ST43 described above, then the procedure goes to StepST52. In the Step ST52, a normal equation (see the Equation (25))employed for obtaining coefficient seed data is produced from thecoefficient data with respect to all the phase shift values.

[0232] Then, in Step ST 53, the normal equation produced in the StepST52 is solved by a method such as sweeping so that the coefficient seeddata for each class can be obtained. Then, in Step ST54, thus-obtainedcoefficient seed data is stored in the memory. After that, theprocessing finishes in Step ST55.

[0233] As described above, the coefficient seed data for each class canbe obtained in the same procedure as that employed in the coefficientseed data production device 150′ shown in FIG. 9, through the processingalong the flow chart shown in FIG. 13.

[0234] Although, in the embodiments described above, a linear equationis employed as the estimated equation for producing the HD signal, thepresent invention is not limited thereto. Alternatively, a high orderpolynomial equation may be employed as the estimated equation.

[0235] Further, in the embodiments described above, the class code CL isdetected, and the coefficient data Wi corresponding to the detectedclass code is used in the estimated prediction calculation. However, itis also conceivable to omit the detected portion of the class code CL.In this case, only one kind of coefficient seed data is stored in theinformation memory bank 135.

[0236] Further, although, in the embodiments described above, the outputimage signal Vout transmitted from the image signal processing section110 is supplied to the display section 11 wherein an image created bythe output image signal Vout is displayed, the output image signal Voutmay be supplied into a recording device such as a video tape recorderwhich records it. In this case, the output image signal Vout may beprocessed in the post-processing circuit 129 in such a manner as to havea data structure optimum for recording.

[0237] Further, in the embodiments described above, the 525 i signal asthe input image signal Vin is converted into the 1080 i signal, the XGAsignal, or the 525 i signal for obtaining an image to be displayed in adifferent magnification, as the output image signal Vout. However, thepresent invention is not limited thereto. It is a matter of course thatthe preset invention is similarly applicable to another cases where afirst image signal is converted into a second image signal using anestimated equation.

[0238] Further, although the embodiments described above have showed theexample where the information signal is an image signal, the presentinvention is not limited thereto. For example, the present invention isalso applicable to a case where the information signal is a soundsignal.

[0239] According to the present invention, when a first informationsignal is to be converted into a second information signal, phaseinformation about a target position in the second information signal isobtained from the information about format or size conversion;coefficient data of an estimated equation is produced from coefficientseed data, based on the resultant phase information; and informationdata of the target position in the second information signal is obtainedusing thus-produced coefficient data. As a result, it becomes possibleto eliminate a necessity of a memory for storing a large amount ofcoefficient data at the time of making conversions into various formatsand sizes, and the apparatus can be structured at low cost.

[0240] Further, according to the present invention, the sum of thecoefficient data of the estimated equation produced using thecoefficient seed data is obtained, and then the information data of thetarget position produced by use of the estimated equation is normalizedwith dividing it by thus-obtained sum. As a result, it becomes possibleto remove the fluctuations in the levels of the information data of thetarget position caused by a rounding error occurred when the coefficientdata of the estimated equation is obtained according to the productionequation using the coefficient seed data.

INDUSTRIAL APPLICABILITY

[0241] As described above, the information signal processor, the methodfor processing the information signal, the image signal processor andthe image display apparatus using the same, the device for producing thecoefficient seed data used for the same and its production method, andan information-providing medium according to the present invention arepreferable for use in the case of converting a format such as a casewhere the 525 i signal is converted into the 1080 i signal, a case wherethe 525 i signal is converted into the XGA signal and the like, orconverting an image size.

What is claimed is:
 1. An information signal processor for converting afirst information signal including a plurality of information data intoa second information signal including a plurality of information data,comprising: conversion information input means for inputting conversioninformation about a format or size conversion; information conversionmeans for converting the conversion information input by the conversioninformation input means into phase information about a target positionin said second information signal; first memory means for storingcoefficient seed data, said coefficient seed data being coefficient datain production equation for producing coefficient data to be used inestimated equation, and said production equation using said phaseinformation as a parameter; coefficient data generation means forgenerating said coefficient data to be used in said estimated equationcorresponding to said phase information about said target position, saidcoefficient data in said estimated equation being produced according tosaid production equation using said coefficient seed data stored in saidfirst memory means and said phase information about said target positionobtained as a result of conversion in said information conversion means;first data selection means for selecting a plurality of firstinformation data located in periphery of said target position in saidsecond information signal, based on said first information signal; andcalculation means for calculating and obtaining information data of saidtarget position based on said estimated equation using said coefficientdata generated in said coefficient data generation means and saidplurality of first information data selected in said first dataselection means.
 2. An information signal processor according to claim1, further comprising: second data selection means for selecting aplurality of second information data located in periphery of said targetposition in said second information signal, based on said firstinformation signal; and class detection means for detecting a classincluding said information data at said target position, based on saidsecond information data selected in said second data selection means,wherein said first memory means stores said coefficient seed dataobtained beforehand for each class detected in the class detectionmeans, and wherein the coefficient data generation means generatescoefficient data of the estimated equation corresponding to the classdetected in said class detection means and the phase information aboutsaid target position.
 3. An information signal processor according toclaim 2, wherein said coefficient data generation means includes:coefficient data production means for producing coefficient data of saidestimated equation for each class detected in the class detection meansaccording to said production equation using said coefficient seed datastored in said first memory means and the phase information about saidtarget position obtained as a result of conversion by said informationconversion means; second memory means for storing the coefficient dataof said estimated equation in each class produced in said coefficientdata production means; and coefficient data read means for reading thecoefficient data of said estimated equation corresponding to the classdetected by said class detection means out of said second memory meansand transmitting the read coefficient data.
 4. An information signalprocessor according to claim 1, further comprising: addition means forobtaining a sum of the coefficient data of said estimated equationgenerated in said coefficient data generation means; and normalizationmeans for normalizing with dividing the information data at said targetposition obtained in said calculation means by the sum obtained in saidaddition means.
 5. An image signal processor for converting a firstimage signal including a plurality of pixel data into a second imagesignal including a plurality of pixel data, comprising: conversioninformation input means for inputting conversion information about aformat or size conversion; information conversion means for convertingsaid conversion information input by said conversion information inputmeans into phase information about a target position in said secondimage signal; memory means for storing coefficient seed data, saidcoefficient seed data being coefficient data in production equation forproducing coefficient data to be used in estimated equation, and saidproduction equation using said phase information as a parameter;coefficient data generation means for generating said coefficient datato be used in said estimated equation corresponding to said phaseinformation about said target position, said coefficient data in saidestimated equation being produced according to said production equationusing said coefficient seed data stored in said memory means and saidphase information about said target position obtained as a result ofconversion in said information conversion means; data selection meansfor selecting a plurality of pixel data located in periphery of thetarget position in said second image signal, based on said first imagesignal; and calculation means for calculating and obtaining pixel dataof said target position based on said estimated equation using saidcoefficient data generated in said coefficient data generation means andsaid plurality of pixel data selected in said data selection means. 6.An image display apparatus comprising: image signal input means forinputting a first image signal including a plurality of pixel data;image signal processing means for converting the first image signalinput from said image signal input means into a second image signalincluding a plurality of pixel data and for outputting the resultantsecond image signal; image display means for displaying an imageproduced by said second image signal received from said image signalprocessing means onto an image display element; and conversioninformation input means for inputting conversion informationcorresponding to a format or a size of the image displayed on said imagedisplay element, wherein the image signal processing means includes:information conversion means for converting said conversion informationinput by said conversion information input means into phase informationabout a target position in said second image signal; first memory meansfor storing coefficient seed data, said coefficient seed data beingcoefficient data in production equation for producing coefficient datato be used in estimated equation, and said production equation usingsaid phase information as a parameter; coefficient data generation meansfor generating said coefficient data to be used in said estimatedequation corresponding to said phase information about said targetposition, said coefficient data in said estimated equation beingproduced according to said production equation using said coefficientseed data stored in said first memory means and said phase informationabout said target position obtained as a result of conversion in saidinformation conversion means; first data selection means for selecting aplurality of first pixel data located in periphery of said targetposition in said second image signal, based on said first imageinformation signal; and calculation means for calculating and obtainingpixel data of said target position based on said estimated equationusing said coefficient data generated in said coefficient datageneration means and said plurality of first pixel data selected in saidfirst data selection means.
 7. An image display apparatus according toclaim 6, further comprising: second data selection means for selecting aplurality of second pixel data located in periphery of the targetposition in said second image signal, based on said first image signal;and class detection means for detecting a class including said pixeldata at said target position, based on said plurality of second pixeldata selected by said second data selection means, wherein said firstmemory means stores said coefficient seed data obtained beforehand foreach class detected in said class detection means, and wherein thecoefficient data generation means generates coefficient data of saidestimated equation corresponding to the class detected in said classdetection means and the phase information about said target position. 8.An image display apparatus according to claim 7, wherein saidcoefficient data generation means includes: coefficient data productionmeans for producing coefficient data of said estimated equation for eachclass detected in said class detection means according to saidproduction equation using said coefficient seed data stored in saidfirst memory means and the phase information about said target positionobtained as a result of conversion in said information conversion means;second memory means for storing the coefficient data of said estimatedequation for each class produced in said coefficient data productionmeans; coefficient data read means for reading the coefficient data ofsaid estimated equation corresponding to the class detected by saidclass detection means out of said second memory means and transmittingthe read coefficient data.
 9. An image display apparatus according toclaim 6, further comprising: addition means for obtaining a sum ofcoefficient data of said estimated equation generated by saidcoefficient data generation means; and normalization means fornormalizing with dividing the pixel data at said target positionobtained in said calculation means by the sum obtained in said additionmeans.
 10. A method for processing an information signal for convertinga first image signal including a plurality of information data into asecond image signal including a plurality of information data,comprising: a first step of inputting conversion information about aformat or size conversion; a second step of converting said conversioninformation input in the first step into phase information about atarget position in the second image signal; a third step of generatingcoefficient data to be used in estimated equation corresponding to saidphase information about said target position obtained as a result of theconversion in the second step according to production equation forproducing said coefficient data to be used in said estimated equationusing coefficient seed data and said phase information about said targetposition, said production equation using said phase information as aparameter, and said coefficient seed data being coefficient data in saidproduction equation; a fourth step of selecting a plurality of firstinformation data located in periphery of the target position in saidsecond information signal based on said first information signal; and afifth step of calculating and obtaining information data of said targetposition based on said estimated equation using said coefficient datagenerated in the third step and said plurality of first information dataselected in the fourth step.
 11. A method for processing an informationsignal according to claim 10, further comprising: a sixth step ofselecting a plurality of second information data located in periphery ofthe target position in said second information signal, based on saidfirst information signal; and a seventh step of detecting a classincluding said information data at said target position, based on saidplurality of second information data selected in the sixth step, whereinin the third step, the coefficient data of said estimated equationcorresponding to the class detected in the seventh step and said phaseinformation about said target position is produced.
 12. A method forprocessing an information signal according to claim 11, wherein thethird step further comprises: a step of producing coefficient data ofsaid estimated equation for each class according to said productionequation for producing the coefficient data of the estimated equationobtained beforehand for each class detected in the seventh step usingthe coefficient seed data and the phase information about said targetposition obtained as a result of conversion in the second step, saidcoefficient seed data being coefficient data of the production equation;a step of storing the produced coefficient data of said estimatedequation for each class into a memory means; and a step of reading saidcoefficient data of said estimated equation corresponding to the classdetected in the seventh step out of the memory means and transmittingthe read coefficient data.
 13. A method for processing an informationsignal according to claim 10, further comprising: an eighth step ofobtaining a sum of coefficient data of said estimated equation generatedin the third step; and a ninth step of normalizing with dividing saidinformation data at said target position obtained in the fifth step bysaid sum obtained in the eighth step.
 14. An information-providingmedium for providing a computer program for, in order to convert a firstinformation signal including a plurality of information data into asecond information signal including a plurality of information data,executing the steps of: a first step of inputting conversion informationabout a format or size conversion; a second step of converting saidconversion information input in the first step into phase informationabout a target position in the second image signal; a third step ofgenerating coefficient data to be used in estimated equationcorresponding to said phase information about said target positionobtained as a result of the conversion in the second step according toproduction equation for producing said coefficient data to be used insaid estimated equation using coefficient seed data and said phaseinformation about said target position, said production equation usingsaid phase information as a parameter, and said coefficient seed databeing coefficient data in said production equation; a fourth step ofselecting a plurality of first information data located in periphery ofthe target position in said second information signal based on saidfirst information signal; and a fifth step of calculating and obtaininginformation data of said target position based on said estimatedequation using said coefficient data generated in the third step and theplurality of said first information data selected in the fourth step.15. A coefficient seed data production device for producing coefficientseed data, said coefficient seed data being coefficient data inproduction equation for producing coefficient data to be used inestimated equation employed when converting a first information signalincluding a plurality of information data into a second informationsignal including a plurality of information data, and said productionequation using phase information as a parameter, comprising: signalprocessing means for performing a thinning-out processing on a teachersignal to obtain a student signal; phase shift means for shifting aphase of said student signal with a phase of information data positionof said teacher signal being gradually changed with respect to saidinformation data position of said student signal; first data selectionmeans for selecting a plurality of first information data located inperiphery of a target position in said teacher signal, based on saidstudent signal having a phase shifted by said phase shift means; normalequation production means for producing a normal equation for obtainingsaid coefficient seed data using the plurality of said first informationdata selected by said first data selection means and the informationdata at said target position in said teacher signal; and coefficientseed data calculation means for solving said normal equation to obtainsaid coefficient seed data.
 16. A coefficient seed data productiondevice according to claim 15, further comprising: second data selectionmeans for selecting a plurality of second information data located inperiphery of a target position in said teacher signal, based on saidstudent signal having a phase shifted by said phase shift means; andclass detection means for detecting a class including said informationdata at said target position, based on said plurality of secondinformation data selected in said second data selection means, whereinsaid normal equation production means produces a normal equation forobtaining said coefficient seed data for each class using the classdetected by the class detection means, the plurality of said firstinformation data selected in said first data selection means, and saidinformation data at said target position in said teacher signal, andwherein said coefficient seed data calculation means solves the normalequation of each class to obtain the coefficient seed data for eachclass.
 17. A method for producing coefficient seed data, saidcoefficient seed data being coefficient data in production equation forproducing coefficient data to be used in estimated equation employedwhen converting a first information signal including a plurality ofinformation data into a second information signal including a pluralityof information data, and said production equation using phaseinformation as a parameter, comprising: a first step of performing athinning-out processing on a teacher signal to obtain a student signal;a second step of shifting a phase of said student signal with a phase ofinformation data position of said teacher signal being gradually changedwith respect to the information data position of said student signal; athird step of selecting a plurality of information data located inperiphery of a target position in said teacher signal, based on saidstudent signal having a phase shifted in said second step; a fourth stepof producing a normal equation for obtaining said coefficient seed datausing the plurality of said information data selected in the third stepand the information data at said target position in said teacher signal;and a fifth step of solving the normal equation produced in the fourthstep to obtain said coefficient seed data.
 18. An information-providingmedium for providing a computer program for, in order to producecoefficient seed data in production equation for producing coefficientdata to be used in estimated equation employed when converting a firstinformation signal including a plurality of information data into asecond information signal including a plurality of information data,said production equation using phase information as a parameter, andsaid coefficient seed data being coefficient data in said productionequation, executing: a first step of performing a thinning-outprocessing on a teacher signal to obtain a student signal; a second stepof shifting a phase of said student signal with a phase of informationdata position of said teacher signal being gradually changed withrespect to the information data position of said student signal; a thirdstep of selecting a plurality of information data located in peripheryof a target position in said teacher signal, based on said studentsignal having a phase shifted in said second step; a fourth step ofproducing a normal equation for obtaining said coefficient seed datausing the plurality of said information data selected in the third stepand said information data at said target position in said teachersignal; and a fifth step of solving the normal equation produced in thefourth step to obtain said coefficient seed data.
 19. A coefficient seeddata production device for producing coefficient seed data, saidcoefficient seed data being coefficient data in production equation forproducing coefficient data to be used in estimated equation employedwhen converting a first information signal including a plurality ofinformation data into a second information signal including a pluralityof information data, and said production equation using phaseinformation as a parameter, comprising: signal processing means forperforming a thinning-out processing on a teacher signal to obtain astudent signal; phase shift means for shifting a phase of said studentsignal with a phase of information data position of said teacher signalbeing gradually changed with respect to the information data position ofsaid student signal; first data selection means for selecting aplurality of first information data located in periphery of a targetposition in said teacher signal, based on said student signal having aphase shifted by said phase shift means; first normal equationproduction means for producing a first normal equation for obtaining thecoefficient data of said estimated equation per phase shift value ofsaid student signal using the plurality of said first information dataselected in said first data selection means and the information data atthe target position in said teacher signal; coefficient data calculationmeans for solving said first normal equation to obtain the coefficientdata of said estimated equation per said phase shift value; secondnormal equation production means for producing a second normal equationfor obtaining said coefficient seed data using the coefficient data persaid phase shift value obtained in the coefficient data calculationmeans; and coefficient seed data calculation means for solving saidsecond normal equation to obtain said coefficient seed data.
 20. Acoefficient seed data production device according to claim 19, furthercomprising: second data selection means for selecting a plurality ofsecond information data located in periphery of a target position insaid teacher signal, based on said student signal having a phase shiftedby said phase shift means; and class detection means for detecting aclass including said information data at said target position, based onthe plurality of said second information data selected in said seconddata selection means, wherein said first normal equation productionmeans produces a first normal equation for obtaining said coefficientdata of said estimated equation of each combination between the classdetected by said class detection means and the phase shift value of saidstudent signal using the class detected by said class detection means,said plurality of first information data selected in said first dataselection means, and said information data at said target position insaid teacher signal; wherein said coefficient data calculation meanssolves the first normal equation to obtain said coefficient data of saidestimated equation of each combination; wherein said second normalequation production means produces a second normal equation forobtaining said coefficient seed data for each class, from thecoefficient data of each combination obtained in said coefficient datacalculation means; and wherein said coefficient seed data calculationmeans solves the second normal equation to obtain the coefficient seeddata for each said class.
 21. A method for producing coefficient seeddata, said coefficient seed data being coefficient data in productionequation for producing coefficient data to be used in estimated equationemployed when converting a first information signal including aplurality of information data into a second information signal includinga plurality of information data, and said production equation usingphase information as a parameter, comprising: a first step of performinga thinning-out processing on a teacher signal to obtain a studentsignal; a second step of shifting a phase of said student signal with aphase of information data position of said teacher signal beinggradually changed with respect to the information data position of saidstudent signal; a third step of selecting a plurality of informationdata located in periphery of a target position in said teacher signal,based on said student signal having a phase shifted in the second step;a fourth step of producing a first normal equation for obtaining saidcoefficient data of said estimated equation per phase shift value ofsaid student signal using the plurality of said information dataselected in the third step and the information data at said targetposition in said teacher signal; a fifth step of solving said firstnormal equation produced in the fourth step to obtain the coefficientdata of said estimated equation per said phase shift value; a sixth stepof producing a second normal equation for obtaining said coefficientseed data using the coefficient data per said phase shift value obtainedin the fifth step; and a seventh step of solving said second normalequation produced in the sixth step to obtain said coefficient seeddata.
 22. An information-providing medium for providing a computerprogram for, in order to produce coefficient seed data in productionequation for producing coefficient data to be used in estimated equationemployed when converting a first information signal including aplurality of information data into a second information signal includinga plurality of information data, said production equation using phaseinformation as a parameter, and said coefficient seed data beingcoefficient data in said production equation, executing: a first step ofperforming a thinning-out processing on a teacher signal to obtain astudent signal; a second step of shifting a phase of said student signalwith a phase of information data position of said teacher signal beinggradually changed with respect to the information data position of saidstudent signal; a third step of selecting a plurality of informationdata located in periphery of a target position in said teacher signal,based on said student signal having a phase shifted in the second step;a fourth step of producing a first normal equation for obtaining saidcoefficient data of said estimated equation per phase shift value ofsaid student signal using the plurality of said information dataselected in the third step and the information data at said targetposition in said teacher signal; a fifth step of solving said firstnormal equation produced in the fourth step to obtain the coefficientdata of said estimated equation per said phase shift value; a sixth stepof producing a second normal equation for obtaining said coefficientseed data using the coefficient data per said phase shift value obtainedin the fifth step; and a seventh step of solving said second normalequation produced in the sixth step to obtain said coefficient seeddata.